Para asombrarse y aprender

Este trabajo presenta la fundamentación, diseño y resultados de un proyecto realizado en el marco de un programa institucional en la UNAM, relacionado con la innovación de la enseñanza experimental. Como producto de este proyecto se elaboró un libro con 30 experimentos de aula dirigidos a profesores de los niveles bachillerato y universitario. Los experimentos elaborados presentan propuestas experimentales novedosas que nos permitan reconceptualizar y diversificar el trabajo práctico

Silicon-Rich Oxide Obtained by Low-Pressure Chemical Vapor Deposition to Develop Silicon Light Sources

Off stoichiometric silicon oxide, also known as silicon-rich oxide (SRO), is a light-emitting material that is compatible with silicon technology; therefore, it is a good candidate to be used as a light source in all-silicon optoelectronic circuits. The SRO obtained by low-pressure chemical vapor deposition (LPCVD) has shown the best luminescent properties compared to other techniques. In spite of LPCVD being a simple technique, it is not a simple task to obtain SRO with exact silicon excess in a reliable and repetitive way. In this work, the expertise obtained in our group to obtain SRO by LPCVD with precise variation is presented. Also, the characteristics of this SRO obtained in our group are revised and discussed. It is demonstrated that LPCVD is an excellent technique to obtain single layers and multilayers of nanometric single layers with good characteristics

La medicina y la enfermedad en Alfonso Reyes

En este ensayo se analizan los síntomas, las enfermedades y las terapias que sufrió el escritor mexicano Alfonso Reyes, reconocido como uno de los escritores más importantes de habla hispana. Se revisa su biografía, que muestra la evolución de sus síntomas cardiovasculares y se documentan las patologías principales que tuvo a lo largo de su vida. Algunas de las enfermedades que sufrió Alfonso Reyes influyeron en su creación literaria, y su condición de enfermo constante lo llevó a reflexiones nada casuales, siendo un ejemplar paciente. Abstract: In this essay, the symptoms, diseases and therapies that the Mexican writer Alfonso Reyes suffered are analyzed. In addition, his biography is reviewed, which shows the evolution of his cardiovascular symptoms and the main diseases and surgeries that he had throughout his life. The diseases suffered by Alfonso Reyes influenced his literary creation and, because of his constant diseases, he made very non-casual l reflections. He was also an exemplary patient

Best match graphs

Best match graphs arise naturally as the first processing intermediate in algorithms for orthology detection. Let T be a phylogenetic (gene) tree T and σ an assignment of leaves of T to species. The best match graph (G,σ) is a digraph that contains an arc from x to y if the genes x and y reside in different species and y is one of possibly many (evolutionary) closest relatives of x compared to all other genes contained in the species σ(y). Here, we characterize best match graphs and show that it can be decided in cubic time and quadratic space whether (G,σ) derived from a tree in this manner. If the answer is affirmative, there is a unique least resolved tree that explains (G,σ), which can also be constructed in cubic time

Estudio de procesos / Programa de mejora electromecánica en JV Muebles de Ocotlán Jalisco

Este documento recopila el análisis obtenido durante las visitas realizadas a las instalaciones de la empresa JV DE OCCIDENTE S.A. DE C.V., dedicada a la fabricación de muebles. Utilizando lo aprendido de la carrera de Ingeniería Industrial, así como de Ingeniería Mecánica se presenta este proyecto en ambos enfoques para realizar dos diferentes bloques uno de ellos (el de Ingeniería Industrial) contiene: levantamiento de layout, documentación de maquinaria y recorridos, estudio de tiempos. En cuanto Ingeniería Mecánica se enfocó en un programa de mejora electromecánica que abarca los siguientes análisis técnicos: • Energía. • Instalaciones Eléctricas. • Mantenimiento. • Seguridad. Para generar una respuesta estandarizada pero enfocada en dicha empresa se ven implicadas las normativas nacionales de STPS (Secretaría del Trabajo y Previsión Social), SENER (Secretaría de Energía), CFE (Comisión Federal de Electricidad), así como de organismos americanos tales NFPA (Asociación Nacional de Protección contra el Fuego) dichas Instituciones y organismos se encargan de regular y normar las situaciones industriales de riesgo, en términos generales se utilizaron para mejorar las condiciones de la empresa.ITESO, A.C

The roles of histone post-translational modifications in the formation and function of a mitotic chromosome

During mitosis, many cellular structures are organized to segregate the replicated genome to the daughter cells. Chromatin is condensed to shape a mitotic chromosome. A multiprotein complex known as kinetochore is organized on a specific region of each chromosome, the centromere, which is defined by the presence of a histone H3 variant called CENP-A. The cytoskeleton is re-arranged to give rise to the mitotic spindle that binds to kinetochores and leads to the movement of chromosomes. How chromatin regulates different activities during mitosis is not well known. The role of histone post-translational modifications (HPTMs) in mitosis has been recently revealed. Specific HPTMs participate in local compaction during chromosome condensation. On the other hand, HPTMs are involved in CENP-A incorporation in the centromere region, an essential activity to maintain centromere identity. HPTMs also participate in the formation of regulatory protein complexes, such as the chromosomal passenger complex (CPC) and the spindle assembly checkpoint (SAC). Finally, we discuss how HPTMs can be modified by environmental factors and the possible consequences on chromosome segregation and genome stability