Abstract Yacon is mainly constituted of water and carbohydrates [single sugars and fructooligosaccharides (FOS)], thus being an excellent alternative for the growth and preservation of bacterial culture. Latilactobacillus sakei ACU-2 and Staphylococcus vitulinus ACU-10 comprised the autochthonous starter culture SAS-1 designed for the manufacture of dry sausages. This study evaluated the use of yacon juice as a potential growth medium and cryoprotectant for these bacteria. The growth medium was prepared with yacon juice supplemented with peptone and dipotassium phosphate. After growing, cells were resuspended in yacon juice (5, 10 and 25 mL/100 mL) and lyophilized. Viable cells were count before, immediately after lyophilization, and along 6 months of refrigerated storage. Both bacteria grew in every yacon concentration tested; however, juice concentration affected their growth. Latilactobacillus sakei grew at μ = 0.256 ± 0.01 giving the highest bacterial density at 10 mL/100 mL (Log DOmax 0.33 ± 0.01). While 5 mL/100 mL yacon juice provided the best conditions for S. vitulinus growth (μ = 0.215 ± 0.016; Log DOmax 0.32 ± 0.01). After lyophilization, the survival rate was 91.1% for L. sakei and 65.8% for S. vitulinus. Throughout storage, high cell counts suggested good stability of both bacteria. Results revealed that yacon juice comprises a nutritive substrate for the growth and cryopreservation of tested strains from the genus Latilactobacillus and Staphylococcus.

Resumo O yacon é constituído principalmente por água e carboidratos (açúcares simples e fruto-oligossacarídeos), sendo uma excelente alternativa para o crescimento e a preservação da cultura bacteriana. Latilactobacillus sakei ACU-2 e Staphylococcus vitulinus ACU-10 compuseram a cultura starter autóctone SAS-1, destinada à fabricação de embutidos secos. Este estudo avaliou o uso do suco de yacon como potencial meio de crescimento e crioprotetor para essas bactérias. O meio de crescimento foi preparado com suco de yacon suplementado com peptona e fosfato dipotássico. Após o crescimento, as células foram ressuspensas em suco de yacon (5, 10 e 25 mL/100 mL) e liofilizadas. As células viáveis foram contadas antes e imediatamente após a liofilização, e ao longo de seis meses de armazenamento refrigerado. Ambas as bactérias cresceram em cada concentração de yacon testada; no entanto, a concentração de suco afetou seu crescimento. Latilactobacillus sakei cresceu a μ = 0,256 ± 0,01, dando a maior densidade bacteriana em 10 mL/100 mL (Log DOmax 0,33 ± 0,01), enquanto a concentração 5 mL/100 mL de suco de yacon apresentou as melhores condições para o crescimento de S. vitulinus (μ = 0,215 ± 0,016; Log DOmax 0,32 ± 0,01). Após a liofilização, a taxa de sobrevivência foi de 91,1% para L. sakei e 65,8% para S. vitulinus. Ao longo do armazenamento, altas contagens de células sugeriram boa estabilidade de ambas as bactérias. Os resultados revelaram que o suco de yacon é um substrato nutritivo para o crescimento e a criopreservação das cepas testadas dos gêneros Latilactobacillus e Staphylococcus.

Abstract: Aspects related to digital competencies in teachers in the higher education scenario in Barranquilla, Colombia, are analyzed. A research was carried out with a mixed approach, applying quantitative and qualitative tools with the support of a Likert type instrument and addressing the topic with a targeted (intentional) sample of 20 teachers. The literature was reviewed to identify the most accepted institutional models for the incorporation of information and communication technologies in academic environments, and the results obtained were compared. The results show a high level of self-perception (over 80%) by the teachers surveyed in view of the presence of digital competences in teaching and learning processes. Among these, training and information, the application of information and communication technologies and the management of learning environments stand out. It is concluded that it is necessary to promote in teachers greater commitment to the renewal of knowledge and information, as well as to stimulate the creation of digital content that promotes the skills in students.

Resumen: Se analizan aspectos relacionados con las competencias digitales en docentes en el escenario de educación superior en Barranquilla, Colombia. Se realizó una investigación con un enfoque mixto, que aplicando herramientas cuantitativas y cualitativas con el apoyo de un instrumento tipo Likert abordó el tema con una muestra dirigida (intencionada) de 20 docentes. Se revisó la literatura para identificar los modelos institucionales más acogidos para la incorporación de las tecnologías de la información y comunicaciones en los ambientes académicos y se contrastó con los resultados obtenidos. Los resultados evidencian una alta autopercepción (superior al 80%) por parte del profesorado encuestado frente a la presencia de competencias digitales en los procesos de enseñanza y aprendizaje. Entre estas, destacaron la capacitación e información, aplicación de las tecnologías de la información y la comunicación y la gestión de entornos de aprendizaje. SE concluye que se debe promover en los docentes mayor compromiso con la renovación del conocimiento y la información, así como la estimular la creación de contenido digital que fomente las competencias en el alumnado.

Abstract: The objective of this article is to analyze how pedagogical strategies in higher education have been transformed by the inclusion of Information and Communication Technologies (ICTs) in recent years. By means of a qualitative approach and an exhaustive documentary review, a detailed analysis of publications since the year 2000 was carried out. The findings and analyses suggest that in recent years there has been an important advance of technology in all aspects of daily life. Additionally, significant contributions were found that show how in Colombia and other countries, the educational scenarios have changed substantially thanks to the technologies that are nowadays applied to support teaching and learning processes. The main conclusion is that the dissemination of pedagogical strategies in teaching-learning processes using ICTs significantly strengthens the teaching work.

Resumen: El objetivo del presente artículo es analizar cómo se han transformado las estrategias pedagógicas en la educación superior con la inserción de las Tecnologías de la Información y las Comunicaciones (TICs) en los últimos años. Mediante un enfoque cualitativo y una revisión documental exhaustiva se realizó un detallado análisis de publicaciones desde el año 2000 en adelante. Los hallazgos sugieren que en los últimos años se ha visto un importante avance de la tecnología en todos los aspectos cotidianos. Adicionalmente, se evidenciaron aportes significativos que muestran como en Colombia y otros países, los escenarios educativos han cambiado sustancialmente gracias a las tecnologías que hoy día se aplican para apoyar el proceso de enseñanza y aprendizaje. Las conclusiones se orientan a que la difusión de estrategias pedagógicas en procesos de enseñanza-aprendizaje mediados por las TIC, fortalece significativamente la labor docente.

This study analyzed what type of adhesive is most suitable for use in the manufacture of Aspidosperma quebracho-blanco wood blockboards impregnated with polyethylene glycol (PEG). Three types of adhesives that could potentially be used to form the boards were analyzed: polyvinyl acetate (PVAc), urea-formaldehyde (UF) and phenol-formaldehyde (PF). Bond quality was determined by the glue-line strength in boards made with impregnated and non-impregnated wood. The use of PEG as a stabilizer of Aspidosperma quebracho-blanco wood did not interfere in the adhesion process when UF and PF adhesives were tested. The PVAc adhesive decreased (<15%) the resistance of the glue line in comparison with the non-impregnated wood. The adhesive that performed the best according to the Spanish standard UNE 56-777-92, pertaining to the determination of glue-line strength, was the UF one. The PVAc and PF adhesives failed to reach the minimum specifications of 10 Nmm-2 even in those boards manufactured with non-impregnated wood.

En este trabajo se evaluó que tipo de adhesivo es factible de utilizar en la fabricación de tableros enlistonados de madera de Aspidosperma quebracho-blanco impregnada con polietilengliol (PEG). Se analizaron tres tipos de adhesivos: polivinil acetato (PVAc), urea-formaldehído (UF) y fenol-formaldehído (PF) para conformar los tableros. La calidad adhesiva se determinó mediante la resistencia de la línea de adhesivo en tableros fabricados con madera impregnada y sin impregnar. El uso de PEG como estabilizante de la madera de Aspidosperma quebracho-blanco no interfirió en el proceso de adhesión cuando se utilizaron adhesivos UF y PF. Con el adhesivo PVAc provocó una disminución (< 15 %) de la resistencia en la línea de adhesivo respecto de la madera sin impregnar. El adhesivo que mejor se comportó de acuerdo a la Norma Española UNE 56-777-92. Determinación de la resistencia en la línea de adhesivo, fue el UF. Los adhesivos PVAc y PF no lograron pasar las especificaciones mínimas de 10 Nmm-2 aún en los tableros fabricados con madera sin impregnar.

En este artículo se demuestra que el operador de Toeplitz Ta con símbolo radial actuando en los espacios de Bergman con peso Ah²(C) es unitariamente equivalente a un operador de multiplicación y se obtienen algunos corolarios de este resultado.

In the article we study the Toeplitz operators defined on the 2-sphere. We show that the Toeplitz operators Ta with radial symbol, acting on the Bergman space A²h(C), is unitary equivalent to a multiplication operator.