ResumenEl uso de biomasa lignocelulósica como fuente de energía renovable se ha convertido progresivamente en un tema fundamental. Grandes esfuerzos se están realizando enfocados en la identificación y caracterización de biomasa adecuada que pueda ser utilizada para el reemplazo de combustibles fósiles convencionales. El principal objetivo del presente estudio es determinar la correlación que existe entre los parámetros del No. Kappa y el contenido de lignina en la paja de trigo y hacer un análisis químico de la paja de trigo que queda como residuo agrícola del cultivo de Trigo en el Valle de Mexicali, México; todo esto para su futuro uso como biocombustible de siguiente generación. Se realizaron los análisis de Humedad, cenizas, Proteína cruda, carbono orgánico, extraíbles en hexano, extraíbles en acetona, extraíbles en agua, No. Kappa, lignina, hemicelulosa y celulosa. Las muestras de paja de trigo fueron posteriormente caracterizadas por Espectroscopia de infrarrojo por transformadas de Fourier para la asociación del contenido de lignina con los resultados reportados. Un factor de correlación de 0.239 entre el No. Kappa y el contenido de lignina se determinó en base a manejo de datos para diferentes tipos de muestras de paja de trigo con la finalidad de poder determinar el contenido de lignina por un método de análisis más sencillo y rápido para estudios posteriores de delignificación de la paja del trigo. AbstractThe use of lignocellulosic biomass as a renewable energy source has gradually become a major issue. Great efforts are being made focused on the identification and characterization of suitable biomass which can be used to replace conventional fossil fuels. Selection of this biomass requires reliable and rapid methods for compositional characterization of plant material. Many standard analytical methods are laborious and slow. The use of simpler and more rapid methods have proved to be invaluable in biomass analysis. The main objective of this study is to determine the correlation between the parameters of Kappa number and the Klason lignin content in different samples of wheat straw with the purpose of determining the lignin content by a simpler and quicker method of analysis. The biomass was examined physiochemically to understand its compositional characteristics through analytical approaches such as gravimetric and volumetric methods. The results indicate 0.239 as a correlation factor between Kappa number y Klason lignin content for wheat straw. Further, Fourier transform infrared spectroscopy was used to indicate characteristic absorption bands of the constituents in the different used samples.

ResumenLa reprobación estudiantil es un problema añejo y complejo que tiene que irse monitoreando cada determinado tiempo en las instituciones de educación superior. El propósito de esta investigación fue identificar las causas de reprobación en las carreras de ingeniería del Instituto Tecnológico de Mexicali, en Baja California, México, desde la perspectiva de los actores educativos principales. En este documento se presentan los resultados obtenidos de los académicos y administradores. La información se recabó mediante una encuesta aplicada en febrero de 2013. El método utilizado es de tipo descriptivo-analítico. Pese a que los orígenes son variados, los académicos y administradores consideran que la principal causa de reprobación de los estudiantes de ingeniería es atribuible al rendimiento escolar del estudiante, es decir problemas relacionados a la falta de hábitos de estudio, de bases para cursar las asignaturas, dificultad para entender la asignatura y no asistir al aula o a las asesorías.Palabras clave: Causas de reprobación, educación superior, perspectiva del académico.

This paper presents the perspective of students and academics on failure in chemical engineering and is part of the results of the Project: "ANALYSIS OF THE CAUSES OF FAILURE IN ENGINEERING IN PUBLIC INSTITUTIONS", which was carried out at the Tecnológico Nacional de México Mexicali campus. A questionnaire was applied to students and academics of the Department of Chemical and Biochemical Engineering to obtain information that allows relating and categorizing the perspective that these educational actors have on the problem of failure. Failure has increased in recent years, due to different factors, which for their study were grouped into psychological, social and family, physical and economic causes and attributable to school performance, the teacher, and the institution. Concluding that from the perspective of students and academics, the causes attributable to school performance, psychological causes and those attributable to the institution are the ones with the greatest influence on failure.

viabilidades de los métodos. Se concluye que el método de liofilización es un método simple y confiable para la preservación a largo plazo el cual presenta menos riesgos de contaminación.Palabras clave: Viabilidad, preservación, liofilización y hongos filamentosos. AbstractMaintain and preserve a collection of fungi is a task that demands constant vigilance and dedication. It requires knowledge of the morphological, physiological and biochemical characteristics of fungi and their requirements in terms of preservation methods. The aim of this study was to assess the viability, purity and macroscopic and microscopic morphological stability of seven strains of filamentous fungi, previously identified in collaborative work by the Technological Institute of Mexicali and the Institute of Agricultural Sciences. The strains identified as Aspergillus niger, Aspergillus awamori, Aspergillus oryzae, Aspergillus flavus, Penicillium chrysogenum, Penicillium sp. and Trichoderma harzianum were subcultured and preserved in dishes on potato dextrose agar (PDA) for 18 months. The preservation was performed by treating conidia obtained from cultures. Conidia were subjected to three different methods of preservation: a) freeze-drying b) soil-sand and c) filter paper. A long-term maintenance is essential for detailed studies of the species. The viability and purity of the fungal species were monitored after 2 month -2 years storage at 10ºC. In preparing the suspension of spores or conidia, Triton X-100 and skim milk were used as stabilizer, and cryoprotectant respectively. The lyophilization method was favorable but destructible compared with the drying method on filter paper, resulting in severe damage to fungal materials which it was reflected in long germinating terms. The method of preservation in soil-sand showed lower viabilities. It is concluded that the freeze-drying method is a simple and reliable method for long-term preservation of the species studied.