Modelación del crecimiento en el ganado blanco orejinegro (Bon) mediante modelos no lineales y un modelo lineal

Se modela la madures sexual del ganado blanco orejinegro (Bon) partiendo que es un recurso genético propio, con necesidad de caracterizar su crecimiento con el fin de mejorar dicho recurso genético. De tal manera que pueda ser utilizado eficientemente en los sistemas de producción bovina de Colombia. se emplearon diferentes modelos estadísticos, para determinar el que mejor se ajusta al crecimiento del ganado Bon, para su análisis se compararon modelos no lineales (brody) y un modelo lineal (Richards). Con el fin de determinar las curvas de crecimiento, utilizando los registros de los animales del programa de la estación agraria paysandú de la universidad nacional de Colombia, sede Medellín ubicada en el municipio de santa Elena todos los animales pertenecientes al hato Bon puro se encontraron bajo las mismas condiciones de alimentación, manejo y sanidad

The impact of voice messaging to boost willingness to participate in oral whole class discussions

Tesis (Magíster en la Enseñanza del Inglés como Lengua Extranjera)This research project explores the alleged benefits of voice messaging via WhatsApp to strengthen willingness to communicate during whole class discussion. The study took place at language institute and 19 adults with an elementary level of English participated. To implement the system 2 WhatsApp groups were created, one for each section, and 3 related interaction resources were designed. The resources names were: Recording opinions via voice messaging prior group in-class conversation, providing remote homework assistance through voice messages and voice messages - driven forums. The intervention lasted little more than a month. After data analysis it was concluded that “recording opinions before group discussions” and “homework assistance” had not been very successful. However, there is some evidence that support the idea that forum based activities using voice messaging sparked a moderate level of willingness to communicate, as well as being helpful for lexical learning and collaborative work.Este estudio explora los aparentes beneficios de la mensajería de voz a través de WhatsApp para aumentar la voluntad de comunicarse durante discusiones que involucran a toda la clase. El estudio se realizó en un instituto de idiomas y conto con 19 participantes los cuales tenían un nivel de inglés elemental. Para implementar el sistema se crearon 2 grupos en WhatsApp, uno por cada curso, además se diseñaron 3 recursos de interacción. Los recursos fueron llamados: grabación de opiniones por mensajes de voz, asistencia remota para tareas usando mensajería de voz y foros generados por mensajería de voz. La intervención duro poco más de un mes y luego de la recolección de datos se concluyó que grabar opiniones y asistencia remota para tareas no fueron efectivas. Sin embargo, hubo evidencia que los foros generaron un moderado grado de voluntad para comunicarse como también se sugiere que podían ser útiles para aprendizaje de léxico y trabajo colaborativ

Spin-orbit and solvent effects in the luminescent [re6q8(ncs)6]4-, q=s, se, te clusters: molecular sensors and molecular devices

Indexación: ScieloRelativistic time-dependent density functional (TDDFT) calculations including spin orbit interactions via the zero order regular approximation (ZORA) and solvent effects using the COSMO model were carried out on the [Re6Q8(NCS)6]4- , (Q = S, Se, Te) clusters. These calculations indicate that the lowest energy allowed electronic transitions are characterized by being of LMCT type. The calculated absorption maximum tends to shift to longer wavelengths as the face-capping chalcogenide ligand becomes heavier. Thus our calculations predict that the [Re6Te8(NCS)6]4- cluster might be also luminescent. Due to the unusual properties exhibited by these and other isoelectronic and isostructural hexarhenium (III) chalcogenide clusters, hexamolybdenum halide clusters and hexatungsten halide clusters, we propose here the design of nanodevices, such as, molecular sensors and molecular nanocells for molecular electronics.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072010000100010&nrm=is

Flavonoids in Agriculture

Flavonoids are compounds that are secondary metabolites, but which play an important role in the biological activities of plants. They can be responsible for the color of flowers and fruits and for the attraction of pollinators. They also participate in plant-microorganism symbiosis. These relationships can be used to naturally control weeds and insect pests and reduce stress and diseases in order to increase crop yield. To improve the understanding of the different biological systems where flavonoids are involved in their symbiotic relationships and in plant physiology, tools such as metabolomics are used, which give a broader picture and allow to search for strategies to solve problems specific to the agricultural sector

“Separata Ambiental”: Criterios orientadores para la transversalización de los acuerdos multilaterales ambientales y su incorporación a la planificación municipal

Este documento, es una propuesta para contribuir con la incorporación de los principales compromisos expresados en las Convenciones Globales Ambientales, en los Planes de Desarrollo Municipal, no solo para una adecuada rendición de cuentas, sino porque se toma conciencia de su contribución al gestionar un desarrollo de la estrategia institucional más adecuada e integral

Establecimiento in vitro de Bambusa vulgaris (Bambú amarillo).

Proyecto de Graduación (Bachillerato en Ingeniería en Biotecnología) Instituto Tecnológico de Costa Rica. Escuela de Biotecnología, 2001.La especie Bambusa vulgaris (bambú) representa un recurso de suma importancia para la industria del papel, la artesanía y la construcción, sin embargo las técnicas tradicionales de propagación no permiten la multiplicación en corto tiempo. El cultivo de tejidos representa una opción para la propagación de B. vulgaris. En la presente investigación tiene como objetivo el establecimiento aséptico in vitro de la especie mencionada. Para ello se realizaron ensayos con tres diferentes explantes: meristemos de tallo, meristemos de rizoma y entrenudos; se aplicaron múltiples tratamientos de desinfección con cloro, alcohol, antibióticos, fungicidas y bactericidas en medios de cultivo MS (1962), a pH 5,7 sin antioxidante, con PVP o carbón activado, en estado sólido o líquido, 20 % de sacarosa. Los meristemos de rizoma respondieron mejor a la desinfección y condiciones in vitro, presentando una oxidación controlable al utilizar medio líquido complentado con Carbón activado (1g/L). Los meristemos apicales se oxidaron en su totalidad. Los entrenudos presentaron una contaminación total por hongos pero no oxidación. El tratamiento que resultó efectivo para la desinfección y control de la oxidación fue aquel en el que se empleó 1 hora mixto Amoxicilina (100mg/L), Ampicilina (100mg/L) y Kilol y Kasumin 1:1 (2 ml/l), 10 minutos en alcohol al 70%, 3 lavados en cámara en medio líquido MS a la mitad complementado con carbón activado

Vector-borne disease risk indexes in spatially structured populations

There are economic and physical limitations when applying prevention and control strategies for urban vector borne diseases. Consequently, there are increasing concerns and interest in designing efficient strategies and regulations that health agencies can follow in order to reduce the imminent impact of viruses like Dengue, Zika and Chikungunya. That includes fumigation, abatization, reducing the hatcheries, picking up trash, information campaigns. A basic question that arise when designing control strategies is about which and where these ones should focus. In other words, one would like to know whether preventing the contagion or decrease vector population, and in which area of the city, is more efficient. In this work, we propose risk indexes based on the idea of secondary cases from patch to patch. Thus, they take into account human mobility and indicate which patch has more chance to be a corridor for the spread of the disease and which is more vulnerable. They can also indicate the neighborhood where hatchery control will reduce more the number of potential cases. In order to illustrate the usefulness of these indexes, we run a set of numerical simulations in a mathematical model that takes into account the urban mobility and the differences in population density among the areas of a city. If i is a particular neighborhood, the transmission risk index TR_i measures the potential secondary cases caused by a host in that neighborhood. The vector transmission risk index VTR_i measures the potential secondary cases caused by a vector. Finally, the vulnerability risk index VR_i measures the potential secondary cases in the neighborhood. Transmission indexes can be used to give geographical priority to some neighborhoods when applying prevention and control measures. On the other hand, the vulnerability index can be useful to implement monitoring campaigns or public health investment.Comment: 16 pages, 5 figure

The impact of transportation investment, road transportation and telecommunications on FDI in Latin America 2008-2021

In this paper, we examine the effects of logistic infrastructures as determinants of foreign investment in Latin America and the Caribbean from 2008 to 2021. We analyze the data using panel data and a feasible generalized least squares model. Our findings indicate that FDI tends to flow to countries with adequate transport and telecommunications infrastructure, although the availability of an electricity grid suitable for the needs of investors is the most significant factor in Latin America. We also determined that there is a limit beyond which investment in transportation infrastructure does not contribute to attracting foreign investment. Furthermore, our analysis shows that the region attracts FDI due to new market opportunities and lower production costs. We also find that the economic opening in Latin America discourages investment by neighboring investors, highlighting the importance of policies that balance foreign capital attraction with respect to international agreements with neighboring countries