Search

Resumen: El objetivo de esta investigación es describir las percepciones de un grupo de estudiantes universitarios de nivel de pregrado en torno a la educación virtual en tiempos de COVID-19. El enfoque es cuantitativo, cuenta con un diseño no experimental-transversal, y es de tipo descriptivo. Se empleó como instrumento un cuestionario tipo Likert con 31 ítems, a una muestra de 608 estudiantes de la facultad de ciencias empresariales de una universidad pública de la ciudad de Cúcuta (Colombia). Los resultados muestran que la educación virtual en tiempos de COVID-19 para el escenario de investigación y la muestra de participantes ha sido adecuada y efectiva en las distintas dimensiones analizadas. Se concluye que la percepción en general de los estudiantes universitarios es favorable frente a la educación virtual, particularmente, respecto del papel que han tenido los docentes en cada uno de sus cursos y materias.

En el presente estudio se analizan las percepciones y habilidades financieras en un grupo de 307 estudiantes de pregrado de una institución educativa superior pública de la ciudad de Ocaña (Colombia). La investigación tiene un enfoque cuantitativo, no experimental transversal de nivel descriptivo, y se enmarca en el paradigma empírico analítico. Se empleó como instrumento un cuestionario tipo Likert de 33 preguntas divididas en tres dimensiones: 1) datos sociodemográficos, 2) percepciones y 3) habilidades-usos. Los datos fueron analizados a través de estadística descriptiva. Los resultados muestran que los estudiantes tienen una percepción y actitud favorable respecto de los temas financieros, aunque se evidencian debilidades en las dimensiones relacionadas con las habilidades-usos financieros. Se concluye que existen limitaciones en el saber-hacer relacionado con la alfabetización financiera y la necesidad del desarrollo de programas específicos focalizados en competencias. The present research study analyzes financial perceptions and skills in a group of 307 undergraduate students from a public higher education institution located in the city of Ocaña (Colombia). The approach is quantitative, non-experimental, cross-sectional, and descriptive and is framed within an analytical empirical paradigm. A 33 question Likert-type questionnaire is applied and divided in three dimensions: 1) socio-demographic data, 2) perceptions, and 3) skills-usage. Collected data are analyzed by descriptive statistics. The results show that students have favorable perceptions and attitudes towards financial issues, although weaknesses are evident in the dimensions related to financial skills-usage. It is concluded that there are limitations on financial literacy know-how and that there is a need for developing specific programs that focus on competencies.

El presente artículo muestra los resultados de una investigación cuantitativa que pretendió determinar el nivel de éxito académico de un grupo de 357 estudiantes colombianos en la presentacion de las pruebas Saber Once con el acompañamiento de una institución de educación superior durante cinco años consecutivos. Los hallazgos demuestran que los resultados en su gran mayoría son positivos año a año, con mayor porcentaje de éxito en las pruebas de lectura crítica y matemáticas. Palabras clave: pruebas Saber 11, acompañamiento institucional, éxito académico, calidad educativa. This article shows the results of a quantitative research that aimed to determine the level of academic success of a group of 357 Colombian students in the presentation of the Saber Once tests with the accompaniment of a higher education institution for five consecutive years. The findings show that the results are mostly positive year by year, with a higher percentage of success in the tests of critical reading and mathematics.

En la universidad todo profesor debe estar imbuido tanto en la actividad científica como en la docencia, y por ello resulta de interés conocer las actitudes de los docentes en torno a la producción de conocimiento científico. Se realizó una investigación cuantitativa, centrada en el análisis descriptivo correlacional-causal de los ítems de un test y un análisis factorial confirmatorio con 130 docentes. Como conclusión, el modelo generado resulta suficientemente explicativo de las variables relacionadas con la producción científica del conocimiento. At university, every teacher must be imbued with both scientific activity and teaching, and it is therefore of interest to know the attitudes of teachers towards the production of scientific knowledge. A quantitative investigation was carried out, centred on the descriptive correlation-causal analysis of the items in a test and a confirmatory factor analysis with 130 teachers. In conclusion, the model generated is sufficiently explanatory of the variables related to the scientific production of knowledge.

Resumen La calidad en la educación exige una completa articulación entre las políticas educativas y aquello que se hace en las aulas. El objetivo del estudio es analizar estos dos factores, aplicados dentro del área de ciencias naturales de una institución educativa colombiana, para los niveles de formación básica y media. Es una investigación de corte cualitativo, de nivel descriptivo, en el que se emplearon el método hermenéutico y la categorización. En el estudio participaron tres docentes de ciencias naturales y educación ambiental, a quienes se les aplicó una matriz de categorización sobre su planeación de asignatura y aula, así como a las políticas de orden nacional. En las políticas, la categoría más relevante es la competencia científica, asociada a la habilidad para realizar investigaciones de carácter científico. Sin embargo, desde la planeación curricular y el ambiente de aula, poco se profundiza en las habilidades propias de esta competencia. Se concluye que la planeación curricular de los docentes y el ambiente de aula, no se ajustan a las políticas educativas, en relación con la enseñanza de las ciencias naturales. Abstract Quality in education requires a complete articulation between educational policies and what is done in the classrooms. The objective of the study is to analyze these two factors, applied within the area of natural sciences of a Colombian educational institution, for the levels of basic and secondary education. It is a qualitative research, descriptive level, in which the hermeneutical method and categorization were used. Three teachers of natural sciences and environmental education participated in the study, to whom a categorization matrix was applied on their subject and classroom planning, as well as on national policies. In politics, the most relevant category is scientific competence, associated with the ability to carry out scientific research. However, from the curricular planning and the classroom environment, little goes into the skills of this competence. It is concluded that the curricular planning of the teachers and the classroom environment do not conform to the educational policies, in relation to the teaching of natural sciences.

espanolSe analiza la forma en que la educacion intercultural es asumida por docentes universitarios de la universidad Francisco de Paula Santander de Colombia adscritos a una facultad de ciencias empresariales, frente a una poblacion estudiantil afectada por el conflicto armado. Se consideraron cuatro variables: conocimiento sobre educacion intercultural, politicas institucionales, aspectos de consideracion de los docentes en terminos de multiculturalidad y practicas de educacion intercultural. Se aplico una encuesta a un grupo de 105 docentes y 420 estudiantes apoyada en el paradigma empirico-analitico, el enfoque cuantitativo y un diseno no experimental/descriptivo. Los resultados muestran que los docentes no tienen un conocimiento claro en torno a la educacion intercultural ni de las particularidades socio-culturales de los estudiantes. Se concluye que lo ideal seria reunir esfuerzos para reconocer todas las caracteristicas de la poblacion culturalmente diversa y reconocer las adecuaciones en materia de politicas, curriculo y pedagogia para hacer coherente las acciones dentro del aula, de acuerdo a las necesidades de los estudiantes EnglishThe way in which intercultural education is assumed by university professors from the university Francisco de Paula Santander in Colombia belonging to the faculty of business who deal with a group of the student directly affected by the Colombian armed conflict. Four variables were considered: knowledge about intercultural education, institutional policies, aspects of consideration of teachers in terms of multiculturalism and intercultural education practices. A survey was applied to a group of 105 teachers and 420 students supported by the empirical-analytical paradigm, the quantitative approach and a non-experimental / descriptive design. The results show that teachers do not have a clear knowledge about intercultural education or the socio-cultural particularities of the student. It is concluded that an ideal situation would be to gather efforts to recognize all the characteristics of the culturally diverse population and recognize the adjustments in policy, curriculum and pedagogy to make coherent actions within the classroom, according to the needs of the students.

El presente artículo muestra los resultados de un estudio que pretendió analizar las diferencias en los es-tilos de aprendizaje entre estudiantes de programas de Ciencias Empresariales de jornada diurna y nocturna de una universidad pública. Para ello, se empleó un estudio cuantitativo no experimental-transversal de ni-vel descriptivo y diseño de campo. Se aplicó el cuestionario de Honey-Alonso sobre Estilos de Aprendizaje (CHAEA) a una muestra de 129 sujetos. Los resultados evidencian una inclinación moderada en los estilos teórico, activo y pragmático en ambos grupos y una no preferencia por el estilo reflexivo. This article shows the results of a study that attempted to analyze the differences in learning styles among students of Business Sciences programs during the day and at night at a public university. For this, a de-scriptive-level, non-experimental-cross-sectional quantitative study, and field design were used. The Honey-Alonso Questionnaire on Learning Styles (CHAEA) was applied to a sample of 129 subjects. The results show a moderate inclination in the theoretical, active, and pragmatic styles in both groups and a non-preference for the reflective style.

This research seeks to analyze the degree of promotion and development of scientific competences based on the document Basic Standards of Competences in Natural Sciences proposed by the Ministerio de Educación Nacional, Colombia, specifically the competences associated with Physics. To this end, a twenty-item questionnaire is designed with a dichotomous response scale. The reliability analysis showed that the proposed scale had a good internal consistency regarding the measurement of scientific competences. The research adopts a quantitative descriptive approach based on the processing of data provided by 87 students from a private educational institution with emphasis on natural sciences in the city of San José de Cúcuta and enrolled between the ninth and eleventh grades. The results identify as a weakness in the teaching process, that teachers do not promote the use and articulation of diverse registers of semiotic representation of a set of data, a situation that limits the process of reasoning and resolution of problematic situations in everyday scenarios where the concepts of physics are present. Likewise, it was observed as a strength that teachers promote attitudinal skills in their students based on mutual respect, cooperative work and good communication. This type of research expands the knowledge that is available on the process of developing scientific competencies in the courses prior to entering higher education, so it is suggested to replicate this research process in students from different social contexts in order to improve the robustness of the questionnaire and provide valuable information to educational institutions on the design of improvement plans.

Resumen Esta investigación tuvo como objetivo analizar los efectos de la aplicación del Programa de Enriquecimiento Instrumental (PEI) de Reuven Feuerstein sobre un grupo de jóvenes infractores en proceso de resocialización de la Fundación El Faro del municipio de San José de Cúcuta, Colombia. Corresponde a un estudio cualitativo de nivel descriptivo enmarcado en la orientación epistemológica del paradigma interpretativo. En el estudio participaron diez jóvenes en proceso de resocialización con diversas características y limitaciones; para la intervención y recolección de información se utilizaron los instrumentos de relaciones virtuales, comparaciones y relaciones espaciales del PEI junto al diario de campo. Los resultados presentados desde la perspectiva cualitativa muestran un conjunto de cambios en las estructuras cognitivas de los jóvenes sujetos a intervención, es decir, sobre las funciones cognitivas y las operaciones mentales, aunque algunos factores limitaron la mediación como el consumo de sustancias psicoactivas y el ambiente del centro de rehabilitación. La evidencia permite concluir que son significativas las potencialidades del programa cognitivo y la Experiencia de Aprendizaje Mediado -EAM- como se señalan en otros estudios sobre los diferentes ámbitos de aplicación de la teoría de la Modificabilidad Estructural Cognitiva. Abstract The objective of this research was to analyze the effects of applying Reuven Feuerstein's Instrumental Enrichment (FIE) Program to a group of juvenile offenders during a resocialization process by Fundación El Faro in the municipality of San José of Cucuta, Colombia. It corresponds to a qualitative, descriptive study framed within the epistemological orientation of the interpretative paradigm. Ten young people with various characteristics and limitations participated in the resocialization process. Virtual relationship instruments, comparisons and FIE spatial relationships were used in the intervention and for information collection, along with the field log. The results presented from a qualitative perspective show a set of changes in the cognitive structures of young people subject to intervention. That is, cognitive functions and mental operations changed, although some factors limited mediation, such as psychoactive substance consumption and the environment within the rehabilitation center. The evidence allows concluding that the Mediated Learning Experience (MLE) and the program's cognitive potentials are significant, as indicated in other studies on the different environments in which the Structural Cognitive Modifiability Theory is applied. Resumo Esta pesquisa teve como objetivo analisar os efeitos da aplicação do Programa de Enriquecimento Instrumental (PEI) de Reuven Feuerstein num grupo de jovens infratores em processo de ressocialização da Fundação El Faro do município de San José de Cúcuta, Colômbia. Trata-se de um estudo qualitativo de nível descritivo enquadrado na orientação epistemológica do paradigma interpretativo. Participaram do estudo dez jovens em processo de ressocialização, com diversas características e limitações. Para a intervenção e coleta de informações, foram utilizados os instrumentos de relações virtuais, comparações e relações espaciais do PEI, juntamente com o diário de campo. Os resultados apresentados na perspectiva qualitativa mostram um conjunto de mudanças nas estruturas cognitivas dos jovens sujeitos à intervenção, ou seja, nas funções cognitivas e nas operações mentais, embora alguns fatores tenham limitado a mediação, como o consumo de substâncias psicoativas e o ambiente do centro de reabilitação. As evidências permitem concluir que as potencialidades do programa cognitivo e da Experiência de Aprendizagem Mediada -EAM- são significativas, conforme apontado em outros estudos nas diferentes áreas de aplicação da teoria da Modificabilidade Estrutural Cognitiva.

Se determinan los impactos socio-económicos y educativos del Covid-19 en un grupo de individuos pertenecientes al sector informal. Corresponde a un estudio cuantitativo de nivel descriptivo y de tipo no experimental, transeccional. La muestra estuvo conformada por 199 sujetos. Se empleó un cuestionario como instrumento de recolección de datos. Los resultados muestran algunos problemas, por ejemplo, debilidades en el aprendizaje real desde casa. Se concluye que las desigualdades sociales, económicas y educativas en este contexto crean barreras y limitaciones. The socio-economic and educational impacts of Covid-19 are determined in a group of individuals belonging to the informal sector. It corresponds to a quantitative study of a descriptive level and of a non-experimental, transectional type. The sample consisted of 199 subjects. A questionnaire was used as a data collection instrument. The results show some problems, for example, weaknesses in real learning from home. It is concluded that social, economic and educational inequalities in this context create barriers and limitations.

The stigmatization of natural sciences and mathematics as difficult, boring and non-practical subjects, starting at the secondary levels, has caused an increased disarticulation between the significant learning of physics and the student, this can be reflected in a less development of basic competences, an almost instinctive revulsion of a large number of students towards these subjects and poor results in the tests that are carried out. Reflecting on this situation, we apply the inquiry-based science education. The intervention was carried out in a private calendar B school in the town of Chía, Colombia; Latitude: 4.85, Longitude: -74.05 4° 51′ 0″. The participants were 80 students, the instruments used to collect the information were: class observations, surveys, interviews, an entrance, an exit test and another after the exit test. Two specific inquiry based-science type activities were designed: laboratory practices and the manufacture of a device by the student. These two activities in turn had matrices with defined evaluation criteria to evaluate the impact of the intervention. The students found in the investigation, a much more conducive environment for their learning and in the end the proposal allowed to identify positive impacts of the inquiry based-science as well as not so desired results.

The use of smartphones and some applications for educational purposes are valuable tools in the laboratory since they are motivating for students and the teacher can take advantage of this advantage for the teaching of physics. The experience is based on the anthropological theory of didactics and the teaching approach in science, technology, engineering, and mathematics. It is proposed to investigate a trigger question in physics. To respond, an application is used that uses the smartphone’s sensors to record the simulation data. The experience is described, and results of its implementation are presented. Methodologically, a qualitative descriptive approach was used in a group of tenth grade students taking the physics course. Finally, it is concluded that the students felt motivated since they felt they participated in the construction of their own learning, supported using technologies that facilitate the integration of knowledge in physics.

This research reports the findings derived from the identification of the difficulties exhibited by a group of 76 students from different grades of basic secondary education in a private educational institution with an emphasis on science education. The students were given a questionnaire presenting five situations based on the Position-Time graph associated with uniform rectilinear motion of particles. The research approach is of a quantitative nature at a descriptive level with a field design, since it was the students who filled in the instrument. It is highlighted as a finding in the opinion of the students that the subject has been seen in class, but due to the teacher’s methodology it is not fully understood by them. The results show that the students have a long list of difficulties mainly due to the lack of articulation of mathematical concepts in physical contexts, a situation that prevents them from analyzing the proposed statements, reasoning about the approaches, and improving in the process of searching for alternative solutions with clear arguments.

This research is based on the usefulness of mobile phones as a tool for students to learn about uniform rectilinear motion in vertical free fall, based on experimental practice. To evaluate whether these mobile devices allow better learning on the subject, a pre-test/post-test design was carried out with 43 students participating in the 9th grade in natural sciences. McNemar and Stuart-Maxwell non-parametric tests were applied. The proposal on the experimental practice gave satisfactory results when comparing the pre-test and post-test, in the analysis of the particular and global form of the answers.

The teaching of science, and specifically physics, has been associated with the acquisition of knowledge with a particular emphasis on problem solving, as an activity that brings students closer to the methodology and meaningful learning of science. However, problem solving is perhaps one of the sources of failure in physics teaching, which requires a careful analysis of this didactic activity. Therefore, the aim of this work is to analyze the development of students’ problem-solving skills in a physics course. An analysis is presented using the quasi-experimental method through the application of a pre-test – post-test, for which a methodological intervention was used based on the problem-solving competence, which focused on identifying errors and difficulties by the students themselves and thus favoring the learning and development of this competence, which allowed the academic progress of the students to be analyzed. It is concluded that the intervention supported by problem solving improves students’ performance, in addition to the positive assessment they make of the process, as well as its influence on the change in pedagogical practice.

The interdisciplinary nature of knowledge is one of the objectives promoted in Colombia, fostering in students the ability to recognize that the curriculum does not work in isolation; if knowledge is complementary, its joint development leads to better academic performance. This research is oriented towards showing an application of the mathematical concept of the slope of the straight line in physics applications, favoring the understanding of the relationships between variables, as occurs with the graphs of kinematics. A group of eleventh grade students from a private educational institution filled in a questionnaire for data collection, based on three situations proposed to answer three open questions in which a reasonably justified answer was required. A part of the group correctly interpreted the graphs by describing the characteristics of the movement in each time interval, but only a few were able to associate the slope of the line as the velocity or acceleration as a function of the variables mentioned in the graph, although their argumentation was based on the angle of elevation of the line.

Several mathematical concepts have application in physics; this paper reports the results of a pedagogical investigation based on the methodology known as didactic engineering, which has been proposed with the aim of improving the skills exhibited by a group of eleventh grade students from a private institution in the interpretation of kinematic graphs. The concept of the slope of the straight line and how this mathematical concept can represent velocity or acceleration according to the variables considered in the kinematics graph provided was enhanced in the pedagogical intervention. This methodology offers a process of internal validation, after comparing the results obtained in a knowledge test at two different points in time (pre-test and post-test). The results allowed us to identify improvements in all students in terms of basic kinematics graph interpretation skills, and a group of students stood out by advancing in more complex reasoning and interpretation processes. These results contribute to the improvement of the pedagogical practices of Physics teachers at secondary and middle school levels, making them more competent when they enter higher education.

El objetivo de este artA­culo fue mostrar las percepciones de los estudiantes universitarios de las carreras de administraciA³n y ciencias contables de una universidad pAoblica de la ciudad de CAocuta, Colombia, en torno a las Normas Internacionales de InformaciA³n Financiera (NIIF) como herramienta gerencial. Lo anterior corresponde a un estudio enmarcado en el paradigma empA­rico-analA­tico y a un enfoque cuantitativo. La investigaciA³n cuenta con un diseA±o no experimental, transversal y de nivel descriptivo. La poblaciA³n en estudio estuvo integrada por 5000 estudiantes y la muestra por 326 individuos de tres programas acadA©micos: contadurA­a pAoblica, administraciA³n de empresas y tecnologA­a en gestiA³n comercial y financiera. Como instrumento se aplicA³ un cuestionario tipo Likert compuesto por 25 preguntas en la que se analizaron las variables aspectos socio-demogrAificos, conocimiento NIIF y NIIF como herramienta gerencial. Cada una de estas variables estuvo integrada por distintas dimensiones y aspectos. Los datos fueron analizados a travA©s de procesos de estadA­stica descriptiva. En tA©rminos generales, la mayorA­a de los estudiantes que participaron en el estudio percibieron que tienen un conocimiento claro y preciso en torno a las NIIF en cada uno de los Aimbitos estudiados, incluyendo su potencial empleo como herramienta gerencial. Se concluye que un porcentaje significativo de estudiantes reconocen las NIIF como una herramienta en el campo gerencial que apoya la toma de decisiones, la gestiA³n contable y financiera, el control de las operaciones de las empresas y su informaciA³n financiera, los procesos de identificaciA³n y anAilisis de problemas operativos, tAicticos y gerenciales, las adecuaciones y adaptaciones tecnolA³gicas.

Mal de piedra no solo reconstruye de forma narrativa los pueblos mineros del estado de Chihuahua, sino también su gente, su forma de vida y sus costumbres. La obra cuenta con características narrativas que alcanzan planos y niveles de interpretación que rebasan la expresión verbal y necesitan ser abordados de forma crítica desde el ámbito literario e ideológico. Planteo la posibilidad de enriquecer el significado de los elementos biográficos y simbólicos, para mostrar su plurisignificiación, presentando un material restaurado y depurado donde se pueda verificar la evolución del texto a través no solo de las diversas etapas de revisión y edición hechas por las dos editoriales que publicaron la obra, sino también por el material que la Biblioteca Universitaria Carlos Montemayor de la UACJ tiene bajo su custodia y que abarca la información que generó y recopiló el autor durante más de cinco décadas de producción intelectual, es decir aproximadamente desde 1965 hasta 2009. Para la elaboración de esta investigación y edición he tratado tres elementos: el estado de cuestión sobre la novela de Montemayor en la literatura latinoamericana, la bibliografía del autor y los parámetros simbólicos que rodean su obra literaria; el texto Mal de piedra como novela con la revisión de la edición publicada por Premiá (1980) al mismo tiempo que el archivo del Fondo Carlos Montemayor, que consta de ocho carpetas que cuentan con los dos mecanuscritos de la obra, la evidencia de la publicación, la película y algunos folletos de presentaciones que componen un total aproximado de 500 páginas. Esto con el fin de recolectar material que no solo reconstruya la obra y las notas del mismo autor, sino buscando enriquecerla para la lectura de otros interesados, especializados o no, con las diferencias que pueden darse en el proceso de publicación. La edición de la obra de Carlos Montemayor, así como la revisión de los aspectos simbólicos e históricos podría generar mayor interés en los lectores e investigadores sobre la obra del autor mexicano, que adquiere importancia no solo por la belleza narrativa, sino por ser una figura de gran relevancia en la literatura del norte. La narrativa de Montemayor ofrece un acercamiento a la tradición mexicana y a conceptos como la familia y la soledad en espacios como la Sierra y los pueblos chihuahuenses, que a veces son olvidados por la literatura.

RESUMEN: Las variantes anatómicas del tronco celíaco (TC) son relevantes en el ámbito quirúrgico e intervencionista. Existen diferentes estudios a nivel mundial que han demostrado las variaciones que puede presentar el TC tanto en longitud como en estructura; dichos estudios han sido realizados predominantemente en población asiática y europea. Por lo anterior, realizamos un estudio que caracterizó esta estructura y que sea referente para la población mexicana. Se analizó una muestra de 50 especímenes cadavéricos humanos embalsamados de origen mexicano. El promedio de longitud del TC a su primera rama fue de 12,44 mm; de su origen a la segunda rama fue de 17,07 mm; y hasta la tercera fue de 19,15 mm. En la muestra de estudio se encontraron variantes en el 20 % de los especímenes, de éstos el 14 % presentaron variantes morfométricas en cuanto a longitud y 6 % en estructura. Respecto a las variantes morfométricas, destacó la presencia de un TC de 3 mm de longitud. En cuanto a las variantes morfológicas dos individuos presentaron un tronco gastro-esplénico con tronco hepato-mesentérico; y el tercero un tronco bifurcado hepato-gástrico con la arteria esplénica naciendo de la arteria hepática común. Éste último no reportado en la literatura.

The use of innovative lightweight materials for structural design in the automotive industry is no longer a novelty. When joining different parts made of these new materials it is clear that adhesives are one of the best solutions. However, the selection of a suitable adhesive for this application and the performance of the joint under real car conditions need to be intensively investigated. In this paper, an extremely ductile acrylic adhesive was selected to bond a commonly used unidirectional carbon fibre reinforced polymer with an environmentally friendly biopolymer in a single lap joint. The strength of the joint was characterised under quasi-static and impact loading at −30, +23 and +80 °C. It was found that the effect of the strain rate on the maximum failure load increased with temperature. A numerical study was also conducted to predict failure at room temperature. While the quasi-static model predicted accurately the joint behaviour, the impact model overestimated the joint strength as a consequence of the bad adhesion found experimentally.

Coupling TiO2 with narrow band gap semiconductors has been a strategy to obtain visible light active photocatalysts. In this work we present, the characterization and photocatalytic results of high-loaded CuO–TiO2 composites prepared by impregnation of TiO2 powder (Evonik, P25) with copper acetate followed by calcination. The resulting composite materials were characterized by X-ray diffraction, nitrogen adsorption/desorption, UV–vis diffuse reflectance, scanning electron microscopy, X-ray photoelectron spectroscopy and time-resolved microwave conductivity. The photocatalysts were used to degrade gallic acid by using low power ultraviolet and visible light emitting diodes (UV-LED and Vis-LED) as light sources. According to the results, the photocatalytic degradation of the pollutant was efficiently converted to several intermediate products and partially mineralized to CO2 by using visible light. These results were explained in terms of an enhancement of the optical and electronic properties of TiO2 by the presence of Cu2O and CuO phases.

The objective of this article is to identify the competencies of students studying the subject of natural sciences - physics at the high school level, in accordance with the curricular guidelines of the Ministerio de Educación Nacional de Colombia. Methodologically, it was based on a quantitative design, using a student perception survey. The results show, from the students’ point of view, that the teachers have knowledge of their discipline, but the follow-up and improvement of their pedagogical practice at the curricular, didactic and evaluation levels is questioned. It is questioned that the processes related to research and the scientific method are not linked to their classes, so that the students’ level of competences is not the ideal one according to what is established from the curricular orientations at a national level.

This article arises as a proposal in view of the need to evaluate the scientific competences promoted by teachers of the subject of physics at the level of basic secondary and secondary technical education. A valid questionnaire was designed from the application of scalar analysis, factorial analysis and content analysis, which is composed of 49 items evaluated by means of a Likert scale with five levels of response. It was applied in a sample of 249 students enrolled in a public educational institution during 2019, characterized by their good results in the area of physics in state tests. The results allowed the identification of strengths in the four dimensions proposed by the Ministerio de Educación Nacional, Colombia (pedagogical, didactic, disciplinary and behavioural), in contrast with some weaknesses within which the evaluation process stands out as the one with the greatest impact, since the students state that this process is assumed by the teacher as a mechanism of pressure and control. When investigating the teachers in a complementary way, positions were determined that were totally opposite to those held by the students, then it is suggested for future research to consider both the students and the teachers as informants and a supervision of the students’ notes as the end of triangulating the results to refine the conclusions, on which future improvement plans will depend.

Due to the depletion of available energy resources, the usage of fossil fuel has increased steadily. Additionally, the gas emissions of fossil fuel proved to be harmful to the environment. Therefore, researches now focus on utilizing second-generation biodiesel that do not compete with edible seed oils but still can be of great use as an alternative to commercially-produced diesel. The purpose of this research is to extract the oil from Annona muricata (Guyabano) seeds and convert it to biodiesel by esterification using hydrochloric acid and transesterification using potassium hydroxide. The average oil yield was 18.92% while the average crude biodiesel yield was 94.76%. The characterization results of the biodiesel composed of 5% guyabano methyl ester in commercial diesel (B5) were all within the limits set by the Philippine National Standards (PNS). However, the water content for the pure biodiesel (B100) was not within the standard range. The kinematic viscosity of B100 is at the maximum limit of PNS. Nevertheless, it suggests that pure Guyabano biodiesel has the potential to be utilized in diesel engines.

Three dead crude oil samples, arising from Chicontepec, Veracruz (Mexico), were characterized in terms of water content; sediment volume; the fraction of insoluble components in pentane; the fraction of saturated, polar, and aromatic compounds; and the acid and base numbers. In addition, the API density, viscosity at various temperatures, and surface tension were measured for each crude. At the end, some correlations between oil composition and surface properties and viscosity are presented. Viscosity and surface tension of these samples are correlated with the fraction of n-pentane insoluble components (asphaltenes) and inversely correlated with the fraction of aromatic compounds. The acid components in the crude oils are correlated with surface tension while the basic components are negatively correlated with it. Finally the base number is correlated with viscosity.

La Educación Ambiental (EA) ha tenido un auge significativo, se trata de una respuesta hacia la necesidad de un cambio social estructural. Sus fundamentos se encuentran tanto en las normas internacionales como locales, y su desarrollo conceptual ha sido amplio y complejo. El objetivo del presente artículo es explorar algunos elementos normativos y conceptuales que fundamentan la EA, así como la adopción de la misma en términos curriculares en Colombia. El método empleado se circunscribe en el análisis documental, razón por la que se abordó una amplia información de la cual se realizaron inferencias de acuerdo al propósito del artículo. Dentro de los resultados, se encontró que la EA ha sido asumida conforme a las características de cada periodo histórico, en especial, del siglo inmediatamente pasado con un gran cúmulo de normas internacionales y nacionales, y que su implementación desde la escuela debe corresponder a una reflexión conjunta y colectiva de todos los actores escolares, tanto en su diseño como implementación. Cualquier enfoque de la educación ambiental resulta válido siempre que corresponda a los objetivos trazados por la escuela en coherencia con las necesidades y problemáticas locales, aquellas de las que son parte los educandos. Se concluye que las normas internacionales y locales en materia de educación ambiental son evidencia de la trascendencia que tiene la protección del medio ambiente y que los enfoques desarrollados desde el terreno conceptual posibiliten el cambio siempre que se integren elementos tanto críticos como cognitivos o socio-cognitivos.AbstractEnvironmental Education (EE) has had a significant growth as a response to the need for structural social change. Its foundations are found in both international and local standards, and its conceptual development has been extensive and complex. The aim of this article is to explore some statutory and conceptual elements underpinning EE, and its adoption in curricular terms in Colombia. The method used is limited to documentary analysis reason why a wide range of information was addressed from which inferences were made according to the purpose of the article. Among the results, it was found that EE has been taken according to the characteristics of each historical period, particularly since the 70’s in the twentieth century with a wealth of international and national standards, and that its implementation from school should respond to a joint and collective reflection of all school actors, both in its design and implementation. Any environmental education approach is valid whenever appropriate to the goals set by the school in line with local needs and problems, which are part of the learners’ reality. It is concluded that international and local environmental education norms are evidence of the importance that environmental protection and the approaches developed from the conceptual change make change possible provided that they integrate both critical and cognitive or socio-cognitive elements. La Educación Ambiental (EA) ha tenido un auge significativo, se trata de una respuesta hacia la necesidad de un cambio social estructural. Sus fundamentos se encuentran tanto en las normas internacionales como locales, y su desarrollo conceptual ha sido amplio y complejo. El objetivo del presente artículo es explorar algunos elementos normativos y conceptuales que fundamentan la EA, así como la adopción de la misma en términos curriculares en Colombia. El método empleado se circunscribe en el análisis documental, razón por la que se abordó una amplia información de la cual se realizaron inferencias de acuerdo al propósito del artículo. Dentro de los resultados, se encontró que la EA ha sido asumida conforme a las características de cada periodo histórico, en especial, del siglo inmediatamente pasado con un gran cúmulo de normas internacionales y nacionales, y que su implementación desde la escuela debe corresponder a una reflexión conjunta y colectiva de todos los actores escolares, tanto en su diseño como implementación. Cualquier enfoque de la educación ambiental resulta válido siempre que corresponda a los objetivos trazados por la escuela en coherencia con las necesidades y problemáticas locales, aquellas de las que son parte los educandos. Se concluye que las normas internacionales y locales en materia de educación ambiental son evidencia de la trascendencia que tiene la protección del medio ambiente y que los enfoques desarrollados desde el terreno conceptual posibiliten el cambio siempre que se integren elementos tanto críticos como cognitivos o socio-cognitivos.AbstractEnvironmental Education (EE) has had a significant growth as a response to the need for structural social change. Its foundations are found in both international and local standards, and its conceptual development has been extensive and complex. The aim of this article is to explore some statutory and conceptual elements underpinning EE, and its adoption in curricular terms in Colombia. The method used is limited to documentary analysis reason why a wide range of information was addressed from which inferences were made according to the purpose of the article. Among the results, it was found that EE has been taken according to the characteristics of each historical period, particularly since the 70’s in the twentieth century with a wealth of international and national standards, and that its implementation from school should respond to a joint and collective reflection of all school actors, both in its design and implementation. Any environmental education approach is valid whenever appropriate to the goals set by the school in line with local needs and problems, which are part of the learners’ reality. It is concluded that international and local environmental education norms are evidence of the importance that environmental protection and the approaches developed from the conceptual change make change possible provided that they integrate both critical and cognitive or socio-cognitive elements.

En el artículo se hace una exploración de la teoría de la Modificabilidad Estructural Cognitiva (MEC) de Reuven Feuerstein, en relación con los ámbitos de aplicación de la misma. Para lo anterior, se ha hecho una recopilación de algunos estudios realizados en América Latina, Estados Unidos y Europa, a fin de identificar los diversos escenarios en que la teoría puede tener aplicación. Los resultados evidencian que la teoría de Feuerstein está ligada al concepto de desarrollo humano y que los sistemas creados con base en la MEC permiten reducir la deprivación cultural de muchas personas sin importar los factores endógenos que le afecten. Abstract: An exploration of Reuven Feuerstein's cognitive structural modifiability (CSM) theory, in relation to the scope of its application, is made in the article. For this reason, a compilation of studies in Latin America, The United States, and Europe, is made, in order to identify the different scenarios in which the theory can be applied. The results show that Feuerstein's theory is linked to the concept of human development and that the systems created, based on the CSM, allow the reduction of the cultural deprivation of many people, regardless of the endogenous factors that affect it.

The use of lightweight materials in the automotive industry for structural parts has been increasing in recent years in order to reduce the overall vehicle's weight. New innovative lighter materials are being developed nowadays to accomplish that objective. In order to keep or even increase passenger's safety, structural parts made of these materials need to withstand static and impact loads within a range of different temperatures along the vehicle's life. The effect of these conditions when joining these dissimilar lighter materials is a critical issue to be considered when designing the car's body. In this paper, the strength under real car conditions of single lap joints (SLP) made of aluminum alloy (AA) bonded to carbon fiber reinforced polymer (CFRP) adherends was studied. A new crash-resistant epoxy adhesive was used to bond these lightweight materials and an extended characterization of its cohesive properties was carried out. The single lap joints were tested at temperatures of −30, +23, and +80 °C under quasi-static and impact loading. The data obtained was used to perform simple numerical models of the single lap joints under static and impact loads. The experimental results showed an expected increase of the joints strength with the strain rate. The joints behavior was highly influenced by the adherends, especially by the aluminum yielding at high and room temperatures. Delamination of the composite was obtained at low and room temperatures, which explained the strain rate dependence of the failure load. The numerical models predicted with good accuracy the strength of the joints under both static and impact loads.

The Corporate Social Responsibility is the contribution of the companies to promote the changes generated in the last decades on of sustainable development in relation with the commitment of the states to act responsibly towards the environment. This trend has had its heyday in the late 80´s and early 90 with the declaration of Rio in Brazil. From this perspective, is a review of the implications the 1992 Rio Declaration to Colombia as a state party and the RSC as a component in the agendas of the actual organizations. For that, it make a thorough review of the literature in order to make a conceptual approach to the term RSC, the RSC legislation analyzing the positions of those who agree and those who oppose, the rules relationed to this area in Colombia and the need to regulate going to examples of other states.

In this work, the performance of three natural surfactants (one produced by a bacteria and two of vegetal origin) in comparison to synthetics surfactants (cationic, anionic, non-ionic and zwitterionic) for its potential use in enhanced oil recovery EOR application was compared. The basis of comparison was basically the surfactant's solutions surface tension (ST) at room temperature, in the presence and absence of brine (salinity of about 4.7%). These measurements were developed to estimate if surfactants will resist reservoir conditions such as 75 °C and high salinities (up to 5%), conditions prevailing in the oil-field of Chicontepec, Veracruz (Mexico). Results of the work showed that biosurfactants could have potential for EOR process. The rhamnolipid produced by Pseudomonas and guar gum natural surfactants developed characteristics as good or even better than the synthetic surfactants normally employed in this process. The rhamnolipid produced by Pseudomonas seems to be a natural surfactant with extremely interesting characteristics. Rhamnolipid solutions yielded quite low ST at low concentrations (i.e.

Summary Biopsy of a swollen, painful, right inguinal lymph node of a 15-year-old boy revealed histoplasmic lymphadenitis. Histoplasmic granulomas were also observed at biopsy of right plantar skin ulcer, thought traumatic in origin. The patient was asymptomatic and had a normal chest x-ray. The subject of primary inoculation of mucocutaneous histoplasmosis is being reviewed. Four previous cases with bona fide extra pulmonary primary mucocutaneous histoplasmosis with a benign course have been reported. Zusammenfassung Die Biopsie eines geschwollenen und schmerzhaften rechtsseitigen Leistenlymphknotens eines 15 Jahre alten Jungen ergab eine histoplasmotische Lymphadenitis. Als daraufhin die Probeexcision von einem vermutlich traumatischen Hautulkus an der rechten Fussohle untersucht wurde, fanden sich auch histoplasmotische Granulome. Der Patient war asymptomatisch und hatte ein normales Rontgenbild der Lungen. Nur vier „bona fide”-Falle von primarer mucokutaner Histoplasmose sind bisher mitgeteilt worden.

El objetivo de este estudio es analizar el concepto de currículo y sus relaciones con la llamada sociedad del conocimiento, la reproducción cultural y la cognición. Desde lo teórico se delimita el concepto de currículo enfatizando en su función principal: la reproducción de la cultura como base de la cognición de los individuos. Se analizan las implicaciones de la sociedad del conocimiento, así como algunas de sus características para encontrar puntos de conexión entre currículo, cultura y sociedad de la información. Además, se exploran los principios y postulados de la teoría de la modificabilidad estructural cognitiva (MEC) de Reuven Feuerstein y el impacto de sus principios en la delimitación conceptual del currículo. Se concluye que la cultura de los sujetos es la base práctica para generar procesos cognitivos basados en el manejo de la información. La cultura y la sociedad del conocimiento ofrecen a la educación el contexto pertinente al cual se debe adaptar el currículo, a fin de responder a la sociedad actual y a los intereses de los educandos. This study analyzes the concept of a curriculum and its relationship to what is known as knowledge society, cultural reproduction and cognition. The theoretic concept of a curriculum is framed, and its main role underlined: to reproduce culture as the basis of cognition of individuals. The study analyzes the implications of a knowledge society as well as some of its characteristics in order to find a common ground between curriculum, culture and information society. Additionally, the study explores the principles and postulates of Reuven Feurenstein's theory of structural cognitive modifiability (SCM) and its impact on the principles of limiting the concept of curriculum. It concludes that a subject's culture is the practical ground on which to construct cognitive processes founded on information. Knowledge society must offer education the relevant context to which to adapt the curriculum in order to answer to today's society and respond to the needs of students. O objetivo deste estudo é analisar o conceito de currículo e suas relações com a chamada sociedade do conhecimento, com a reprodução cultural e a cognição. A partir da teoria, delimita-se o conceito de currículo e enfatiza-se sua função principal: a reprodução da cultura como base da cognição dos indivíduos. Analisam-se as implicações da sociedade do conhecimento, bem como algumas de suas características para encontrar pontos de conexão entre currículo, cultura e sociedade da informação. Além disso, exploram-se os princípios e postulados da teoria da Modificabilidade Estrutural Cognitiva (MEC), de Reuven Feuerstein, e o impacto de seus princípios na delimitação conceitual do currículo. Conclui-se que a cultura dos sujeitos é a base prática para gerar processos cognitivos baseados na gestão da informação. A cultura e a sociedade do conhecimento oferecem à educação o contexto pertinente ao qual se deve adaptar o currículo afim de responder à sociedade atual e aos interesses dos educandos.

Streptococcus phocae is a beta-haemolytic bacterium that causes systemic infections in Atlantic salmon, Salmo salar L., cultured in southern Chile and also in seals. In this study, the host-pathogen interaction between S. phocae and seven types of cell lines (fish and mammalian) was examined using an indirect fluorescent antibody and confocal microscopy (CM). Chinook salmon embryo (CHSE-214), epithelioma papulosum cyprini (EPC), salmon head kidney (SHK-1) and Atlantic salmon kidney were used as the fish cell lines, while human cervix epithelial adenocarcinoma (HeLa), African green monkey kidney fibroblast (Cos-7) and mouse leukaemic monocyte macrophage (Raw 264.7) were included as mammalian cell lines. Streptococcus phocae type strain ATCC 51973(T) and isolates LM-08-Sp and P23 were selected as representatives from the salmon and seal host, respectively. For the CM examination, monolayers seeded on round coverslips were studied at 2- and 20-h post-inoculation (pi). The results showed that there is no common infectivity pattern between the three S. phocae strains at 2-h pi and the cell lines tested, regardless of the source of isolation (seal or salmon). All S. phocae strains could internalize and were found inside the fish and mammalian cell cytoplasm after 20-h pi. Regardless of the cells studied (fish or mammal) and incubation (2 and 20 h), S. phocae was never observed inside the nuclei. Seal and salmon isolates showed the highest number of bacteria entering into the primate cell lines (HeLa and Cos-7) from 2-h pi, while ATCC 51973(T) was not found outside or inside the HeLa and Cos-7 cells.

Streptococcus phocae is an emerging pathogen for Chilean Atlantic salmon, Salmo salar, but the factors determining its virulence are not yet elucidated. In this work, cell surface-related properties such as hydrophobicity and haemagglutination, adhesion to mucus and cell lines, capsule detection, survival and biofilm formation in skin mucus and serum resistance of the isolates responsible for outbreaks in Atlantic salmon and seals were examined. Adhesion to hydrocarbons and the results of salt aggregation tests indicated most of the S. phocae were strongly hydrophobic. All isolates exhibited a similar ability to attach to the Chinook salmon embryo (CHSE) cells line, but were not able to enter CHSE cells. Haemagglutination was not detected. Our data clearly indicate that S. phocae can resist the killing activity of mucus and serum and proliferate in them, which could be associated with the presence of a capsular layer around the cells. Pathogenicity studies using seal and fish isolates demonstrated mortality or pathological signs in fish injected only with the Atlantic salmon isolate. No mortalities or histopathological alterations were observed in fish injected with extracellular products.

Cerebral amyloid angiopathy is considered pathogenic in non traumatic cerebral lobar hemorrhages.To study the frequency of cerebral amyloid angiopathy in brains of patients dying of non traumatic cerebral hemorrhages.Thirty seven brains from patients, 25 men and aged 65 +/- 10 years old, with cerebral hemorrhages (14 lobar, 18 in basal ganglia and 5 in cerebellum or brainstem) were studied. As controls, the brains of 30 subjects, 14 men and aged 64 +/- 16 years old, dying of non neurological causes were studied. Deep and cortical vessels were stained with hematoxylin eosin, Gomori, Thioflavin T and Bodian. Definitive cerebral amyloid angiopathy was diagnosed when amyloid deposition was observed in the media of vessels.Twenty six out of 32 patients dying of cerebral hemorrhage and 3 of 21 controls had chronic hypertension. Cerebral amyloid angiopathy was present in 19 of 37 brains of patients with cerebral hemorrhage and 13 of 30 control brains. In patients with hypertension, vascular changes independent of the location and volume of amyloid deposition, were observed. Such changes were dilatation, tortuousness, thickening of walls specially in muscular and adventitia and hyaline degeneration. Thirteen brains with hemorrhage had fibrinoid necrosis and 10 had microaneurysms.In this series of patients, cerebral amyloid deposition was unspecific and its role in the pathogenesis of cerebral hemorrhages was not confirmed. Hypertension was associated with vascular degenerative changes that can lead to cerebral hemorrhages.

There is little information about the precise location of the squamous columnar mucosal junction in the Chilean population.To study endoscopically, the location of the squamous columnar mucosal junction in patients with esophageal disease.The location of the squamous columnar mucosal junction was prospectively studied by endoscopy in 347 subjects with normal upper gastrointestinal endoscopy, 117 patients with chronic gastroesophageal reflux without esophagitis, 117 patients with erosive esophagitis, 63 patients with short Barret's esophagus and 28 patients with an extensive Barret's esophagus.No differences in the mucosal junction location were observed between controls and patients with gastroesophageal reflux or erosive esophagitis. In patients with Barret's esophagus, the junction was more proximal. In women, the junction was three cm more proximal than in men, probably due to their shorter stature.Women have a more proximal squamous columnar mucosal junction than men.

The signet ring variant of lobular mammary carcinoma is aggressive and metastasis to serosal surfaces. We report a 46 years old woman presenting with an intestinal obstruction due to a peritoneal carcinomatosis secondary to a signet ring cell carcinoma of the breast. After surgery, the patient received chemotherapy (5-fluorouracil, adriamycin, cyclophosphamide and tamoxifen). A satisfactory response, with regression of peritoneal carcinomatosis and a good quality of life, was achieved. The patient is alive after 2 years of diagnosis.

Recent studies have associated preeclampsia with hypocalciuria, nevertheless others do not show association. We proposed to determinate if this association exists, so we studied 25 term pregnancies patients (13 normotensives, 7 transient hypertension and 5 preeclamptic). We did not find significative differences in the hematocrit, serum calcium, serum creatinine, platelets count and the 24 hour diuresis between these groups. The serum uric acid was significative lower in the normotensive group (3.5 +/- 0.8 mg/dl) than in the preeclamptic group (4.9 +/- 0.89 mg/dl) (mean +/- SD) (p0.05). The 24 hour calciuria was lower in the preeclamptic group (121 +/- 78 mg/24 hours) than in the normotensive (256 +/- 71 mg/24 hours) and transient hypertension group (229 +/- 93 mg/24 hours) (p0.05). We measured the creatinine clearance and the fractional excretion of calcium in the transient hypertension and the preeclamptic groups, there was significative difference only in the fractional excretion of calcium (2.5 +/- 0.8% and 1.1 +/- 0.8% respectively) (p0.05). All the patients had a good clinical evolution, so the arterial pressure returned to normal values in a mean period within 7 days in both groups. There were 3 newborn who were small for gestational age (1 in the transient hypertension and 2 in the preeclamptic group). The difference we found in the 24 hour calciuria and the fractional excretion of calcium agree with the finds of other authors, further prospective studies are needed to understand the physiology and pathophysiology of calcium metabolism in normal, transient hypertension and preeclamptic pregnancy.

In order to eludicate possible mechanism(s) involved in the blood pressure reduction induced by potassium (K) supplementation, we studied the changes of BP and of some of its regulatory systems, including levels of urinary kallikrein (UKal)--an index of renal kallikrein production. Twenty-four untreated essential hypertensives, with a basal BP of 147/96 +/- 13/7 mmHg and normal renal function, received in crossover, double-blind, randomised fashion, 64 mmol KCl or placebo during two periods of 4 weeks each. At the 4th week of potassium supplementation systolic, diastolic and mean BPs decreased by 6.3 +/- 2 (P less than 0.01), 3.0 +/- 2 and 4.1 +/- 2 (P less than 0.05) mmHg respectively for the supine position, and 5.0 +/- 2, 4.0 +/- 2 (P less than 0.05) and 4.0 +/- 1 (P less than 0.05) mmHg for the standing position. Urinary potassium (K) increased from 55 +/- 4 to 123 +/- 6 mmol/24 hours (P less than 0.001) and UKal from 692 +/- 69 to 1052 +/- 141 mU/24 hours (P less than 0.01). Serum K rose from 3.8 +/- 0.1 mEq/l to 4.1 +/- 0.1 mmol/l (P less than 0.001) and PRA from 0.77 +/- 0.12 to 0.99 +/- 0.14 ng/ml/h (P less than 0.05). Correlations were observed between UKal and urinary K (r = 0.44, P less than 0.0001); between differences in UKal and urinary K and in UKal and urinary Na (r = 0.50, P less than 0.0005 and r = 0.48, P less than 0.001 respectively).(ABSTRACT TRUNCATED AT 250 WORDS)