The introduction of real numbers in secondary education. An institutional analysis of textbooks

In this paper we analyse the introduction of irrational and real numbers in secondary textbooks, and specifically the propositions on how these should be taught, in a sample of Brazilian textbooks used in state schools and approved by the Ministry of Education. The analyses discussed in this paper follow an institutional perspective (using Chevallard's Anthropological Theory of Didactics). Our results indicate that the notion of irrational number is generally introduced on the basis of the decimal representation of numbers, and that the mathematical need for the construction of the field of real numbers remains unclear in the textbooks. It seems that textbooks used in secondary teaching institutions develop mathematical organisations which focus on the practical block

Distributional and economy-wide effects of post-conflict policy in Colombia

As part of the 2016 peace accord in Columbia, agricultural policies were proposed for rural regions most affected by an armed conflict that had gone on for decades. We evaluated the effects of these policies with particular attention to their economy-wide and distributional effects. We used a newly built 2014 social accounting matrix for Colombia to calibrate an extended version of the well-known PEP 1-1 Computable General Equilibrium model. The policies we considered were an increase in total factorial productivity because of infrastructure construction and greater technical assistance and employment subsidies intended to promote the substitution of illicit crops. We found that value added, demand for labor, and factor incomes increased in the areas most affected by the conflict while the opposite occurred in the other areas. Moreover, total rural income increased as long as the financing mechanism did not involve an increase in the taxation of rural incomes. In general, distributional effects were strongly conditional on the financing mechanism adopted by the government.Facultad de Ciencias Económica

Integrable Wilson loops in ABJM: a YY-system computation of the cusp anomalous dimension

We study the integrability properties of Wilson loops in the ${\cal N}=6$ three-dimensional Chern-Simons-matter (ABJM) theory. We begin with the construction of an open spin chain that describes the anomalous dimensions of operators inserted along the contour of a 1/2 BPS Wilson loop. Moreover, we compute the all-loop reflection matrices that govern the interaction of spin-chain excitations with the boundary, including their dressing factors, and we check them against weak- and strong-coupling results. Furthermore, we propose a $Y$-system of equations for the cusped Wilson line of ABJM, and we use it to reproduce the one-loop cusp anomalous dimension of ABJM from a leading-order finite-size correction. Finally, we write a set of BTBA equations consistent with the $Y$-system proposal.Comment: 44 pages, 2 figures; v2: clarifications added and typos corrected. Version to appear in JHE

Conmemoración del republicanismo en 1910: reinvención patrimonial y proyección modernista

El trabajo realiza una dilucidación acerca de las implicaciones que tuvo la celebración del primercentenario de la independencia en Colombia en 1910 en lo que refiere a la reinvención patrimonialy la edificación y proyección de un imaginario de nación, que tendría sus particularidadesy condicionantes en el contexto que se desarrollaba así como una interpretación del pasadoespecífica. Se plantea entonces una propuesta de análisis: en primer lugar, la memoria de unpasado originario, luego, su teatralización en el presente, y finalmente, la proyección de un futuroen términos de “progreso”. Así mismo se busca dar cuenta de los fenómenos nacionalistas, quedesplegados durante la celebración, legitimaron la plataforma política de la generación centenarista

Plan de posicionamiento para una nueva marca de carne de res premium en el mercado colombiano

Para que un producto sea exitoso en el mercado se necesita conocer sus potenciales clientes y las necesidades que necesitan ser satisfechas. Este trabajo realiza un estudio de mercado sobre el consumidor de carne premium en Colombia en donde se puntualiza que conocimiento tiene sobre los productos y cual es la forma más certera de abordarlos. Se encontró que la forma más apropiada para llegarle a este tipo de cliente en la ciudad de Bogotá es teniendo un producto con un buen recubrimiento de grasa, madurado, con un marmoleo medio, en donde la marca realice trabajos de ganadera sostenible verde y con un canal de distribución superior tipo Carulla.Agropecuaria Dalmaru SASFor a product to be successful in the market you need to know its potential customers and the needs that need to be met. This paper carries out a market study on the consumer of premium meat in Colombia where it is pointed out that knowledge they habe about the products and what is the most accurate way to address them. It was found that the most appropriate way to reach this type of customer in the city of Bogotá is to have a product with a good fat coating, mature, with a medium marbling, where the brand performs sustainable green livestock work and with a upper distribution channel Carulla type.Administrador (a) de EmpresasPregrad

Evaluation of the Thermal Performance of Two Passive Facade System Solutions for Sustainable Development

Sustainable development is essential for the future of the planet. Using passive elements, like ventilated facades based on insulation and air chambers, or living walls, which are solutions based on nature, is a powerful strategy for cities to improve their thermal environment, reduce energy consumption, and mitigate the effects of climate change. This approach allows for the quantification of the influence of passive surfaces on energy fluxes compared to bare surfaces. In addition, it delves into understanding how the incorporation of vegetation on building facades alters surface energy fluxes, involving a combination of physical and biochemical processes. This comprehensive investigation seeks to harness the potential of passive and natural solutions to address the pressing challenges of urban sustainability and climate resilience. This research uses a surface energy balance model to analyze the thermal performance of two facades using experimental data from a PASLINK test cell. This study uses the grey box RC model, which links continuous-time ordinary differential equations with discrete measurement data points. This model provides insight into the complex interplay among factors that influence the thermal behavior of building facades, with the goal of comprehensively understanding how ventilated and green facades affect the dynamics of energy flow compared to conventional facades. The initial thermal resistance of the bare facade was 0.75 (°C m2)/W. The introduction of a ventilated facade significantly increased this thermal resistance to 2.47 (°C m2)/W due to the insulating capacity of the air chamber and its insulating layer (1.70 (°C m2)/W). Regarding the modular living wall, it obtained a thermal resistance value of 1.22 (°C m2)/W (this vegetated facade does not have an insulating layer). In this context, the modular living wall proved to be effective in reducing convective energy by 68% compared with the non-green facade. It is crucial to highlight that evapotranspiration was the primary mechanism for energy dissipation in the green facade. The experiments conclusively show that both the modular living wall and open-ventilated facade significantly reduce solar heat loads compared with non-passive bare wall facades, demonstrating their effectiveness in enhancing thermal performance and minimizing heat absorption

Effect of pruning on Jatropha curcas L. seedlings during the nursery stage

Objective. The aim was to assess the effect of pruning on Jatropha curcas L. seedlings during the nursery stage. Design/Methodology/Approach. In order to determine the effect of pruning on Jatropha curcas L. seedlings under nursery stage, a study was carried out at the nursery of the CPA “Abel Santamaría” of the Martí municipality, Cuba. A complete randomized design was used. Three treatments (T) were tested: 1) control (without pruning), 2) pruning at 30 cm from the soil and defoliation of seedlings, 3) pruning at 30 cm from the soil and without defoliation of seedlings. Descriptive analysis was performed to determine survival, regrowth and quantity of plants with primary branches. For the number of leaves and branches, height and diameter, a simple variance analysis was used, with partitions for each observation. Results. It was found that no treatment influenced the plant survival and regrowth. With T2 and T3 up to 2 branches per plant obtained. The height was higher with T1 (38,63 cm) and differed from T2 and T3. The highest quantity of branches that formed primary branches was obtained by pruning and without defoliating (28 vs. 22 and 0, for T2 and T1, respectively). Study Limitations/Implications. Pruning is an option to increase agronomic yield in Jatropha, but it has not been studied at nursery conditions. Findings/Conclusions. It is concluded that pruning J. curcas seedlings in nursery at 30 cm of height with regards to the soil, with defoliation or without defoliation; neither affects crop survival or regrowth and the development of primary branches. However, it is possible to obtain more plants with primary branches and higher stem diameter by performing pruning without defoliation.Objective: To determine the effect of pruning on seedlings of Jatropha curcas L. during the nursery stage.Design/Methodology/Approach: To determine the effect of pruning on Jatropha curcas L. seedlings during thenursery stage, a study was carried out at the nursery of the CPA “Abel Santamaría” of the Martí municipality,Cuba. A complete randomized design was used. Three treatments (T) were tested: 1) control (without pruning),2) pruning 30 cm above the soil and seedling defoliation, 3) pruning 30 cm above the soil and without seedlingdefoliation. A descriptive analysis was carried out to determine the survival, regrowth, and number of plantswith primary branches. For the number of leaves and branches, height, and diameter, a simple analysis ofvariance was used, with partitions for each observation.Results: No treatment influenced the survival and regrowth of the plant: up to 2 branches of T2 and T3 wereobtained per plant. A greater height was recorded with T1 (38.63 cm) and this result is different from T2 andT3. The highest number of branches that formed primary branches was obtained by pruning and withoutdefoliation (28 vs. 22 and 0, for T2 and T1, respectively).Study Limitations/Implications. Pruning is an option that can increase Jatropha’s agronomic yield, but it hasnot been studied under nursery conditions.Findings/Conclusions. The pruning of J. curcas seedlings at 30 cm above the ground, under nurseryconditions, with or without defoliation, does not affect the survival or regrowth of the crops and thedevelopment of the primary branches. However, more plants with primary branches and a wider stemdiameter can be obtained by pruning without defoliatio

Formulación del modelo de gestión de procesos, bajo el enfoque de aseguramiento de la calidad, basado en el ciclo de mejora continua Phva de Edwards Deming, para el laboratorio de la industria académica en desarrollo de software, para la facultad de ingeniería de la UCO

En la actualidad el desarrollo de software ha sido una de las tantas líneas de procesos existentes que ha tenido un gran apogeo, esto debido a que las compañías están en la exploración constante de estandarizar y mejorar sus procesos, volviéndolo más sistemáticos y eficientes. En Colombia existen varias universidades dedicadas al desarrollo de software, donde se encuentran espacios prácticos de enseñanza relacionados al programa de Ingeniería de Sistemas que le sirve de guía al estudiante para crear, implementar y administrar diferentes soluciones de software que contribuyan al desarrollo de empresas tanto públicas como privadas, buscando aumentar los indicadores de productividad y optimizar diversos procesos, además de crear valor agregado y promover buenas prácticas con el objetivo de presentar soluciones que se ajusten a las principales problemáticas que se presenten en las diferentes operaciones diarias en la industria, y lo más importante, que esas soluciones que se planteen además de suplir las necesidades, sean soluciones o alternativas que aseguren la calidad en los diferentes procesos. En Colombia, los principales laboratorios de desarrollo de Software se encuentran localizados en ciudades como Villavicencio, Bucaramanga y Medellín.Currently, software development has been one of the many existing process lines that has had a great boom, this is because companies are constantly exploring to standardize and improve their processes, making them more systematic and efficient. In Colombia there are several universities dedicated to software development, where there are practical teaching spaces related to the Systems Engineering program that serves as a guide for students to create, implement and manage different software solutions that contribute to the development of both public and private companies, seeking to increase productivity indicators and optimize various processes, in addition to creating added value and promoting good practices in order to present solutions that fit the main problems that arise in the different daily operations in the industry, and most importantly, that these solutions that are raised in addition to meeting the needs, are solutions or alternatives that ensure quality in different processes. In Colombia, the main software development laboratories are located in cities such as Villavicencio, Bucaramanga and Medellín.Rionegr

Institucionalización y gestión integral sostenible con participación ciudadana de los servicios de agua y saneamiento en la provincia de Urubamba del departamento del Cusco

Con el reconocimiento del derecho al agua potable por las Naciones Unidas y el Objetivo 6 de los Objetivos de Desarrollo Sostenible (ODS), se ha establecido el eje de las políticas nacionales con relación a los servicios de agua y saneamiento, en torno al cual los países de América Latina realizan los esfuerzos para hacer que estos servicios sean universales, de calidad y sostenibles; no obstante existen limitantes en la institucionalización de las prestadoras encargadas de la gestión de los servicios de agua y saneamiento generando ineficiencia de la gestión con la consecuencia de servicios sin valor público, por lo que la población al no valorar el producto de dicho servicio, hace mal uso de los mismos, derrochando y despilfarrando sin la menor responsabilidad, convirtiéndose en un círculo vicioso la débil gestión, por la débil institucionalización y la poca valoración de los servicios de agua y saneamiento. La presente investigación pretende proponer lineamientos y mecanismos para la construcción del círculo virtuoso con la gestión integral con participación ciudadana de los servicios de agua y saneamiento, como una forma de otorgar valor público a estos servicios, el mismo que retroalimenta a la buena gestión de la prestadora municipal

SISTEMAS SILVOPASTORILES EN EL CONTEXTO CUBANO

Los Sistemas Silvopastoriles en Cuba (SSC) se han desarrollado en la práctica a partir de resul- tados de investigaciones realizadas desde la década de los 80, donde se proyectó mejorar la pro- ductividad de los pastos naturales a través de la introducción de valiosas especies de legumino- sas herbáceas y leñosas. Esas investigaciones también determinaron los elementos esenciales del manejo de pastos, como cargas óptimas para sistemas de bajos insumos y métodos de pastoreo adecuados para lograr la sostenibilidad de los pastizales.Entre los diversos tipos de SSC desarrollados, los Bancos de Proteína (BP) y las Asociaciones de leñosas con gramíneas en toda el área (ATA) han mostrado los resultados más importantes, en la producción tanto de carne como de leche, y se perfilan todavía como sistemas que pueden ser generalizados, integrados a los propósitos productivos de crianza de ganado en el país.Dentro de los resultados más importantes en producción de carne bovina se pueden citar ga- nancias de 500-600 g/animal/día y producción de 800 kg de carne/ha/año, con carga cercana a 2 UGM/ha. En leche, producciones de 7-8 kg de leche/vaca/día o 14-16 kg/ha/día, sin suplementos energético-proteicos. En novillas para reemplazo, ganancias diarias entre 400-500 g/animal/día, con peso de incorporación a la reproducción de 290-300 kg a edades entre 20 y 27 meses.Con estos sistemas se logran índices adecuados de rentabilidad y la autosostenibilidad de las unidades productivas, en función de un manejo racional, con gastos mínimos en insumos. A su vez, se logra la recirculación máxima de los nutrientes y la protección y el mantenimiento del medio ambiente