Impacto del Plan Nacional de Lectura y Bibliotecas (PNLB) sobre el número de libros leídos en Colombia

El presente documento evalúa, a través de la metodología Propensity Score Mat-ching, el impacto que ha tenido el Plan Nacional de Lectura y Bibliotecas —PNLB— sobre la cantidad de libros que leen los colombianos. Las conclusiones arrojadas por el estudio permiten corroborar la veracidad de la hipótesis según la cual se afirma que, aquellos individuos pertenecientes a municipios beneficiados por el PNLB, tienen mejores hábitos de lectura que otros con características similares pero que no han sido objeto de atención. Así se proveen criterios objetivos que demuestran la conveniencia de fortalecer el programa en poblaciones ya beneficiadas, y de estimular a los municipios que aún no se han beneficiado del Plan, para que cumplan con los requerimientos exigidos de manera que puedan ser elegibles

Peat Improvement Under Vacuum Preloading:a Novel Approach for Bog Roads in Ireland

This paper presents the preliminary findings of a TCD/NRA vacuum preloading field trial that is part of a research project into the construction options for improving rampart roads. Vacuum preloading is a construction method used to accelerate settlement and the increase shear strength by applying a vacuum pressure to the ground by means of prefabricated vertical drains, an impervious tight sheet and a vacuum pump. Consolidating the ground by applying a vacuum load has several advantages over other techniques, for example; no fill material is required; construction periods are generally shorter; and there is no need for chemical admixtures. This paper presents a review of the literature and describes the setup and initial stage of the TCD/NRA vacuum preloading field trial, that is currently being carried out at Ballydermot bog

Evaluation of a customer loyalty strategy with system dymamics

The customer loyalty programs are a tool of differentiation and high impact to create long term relationships with customers of a company, so as to achieve an improvement in the portfolio and collections, redu­ced costs of customer service, increased revenue from higher sales to the most profitable customers, cross selling, among many other benefits. Ac­cordingly, we present a system dynamic model to analyze the economic benefits, in terms of profitability, which would be to implement a customer loyalty strategy. To adjust and validate the proposed model, its implemen­tation is done in a real case of a marketer of agricultural products in the department of Valle del Cauca - Colombia. The simulation results show that indeed the model fulfills its purpose, and that the loyalty program achieved significant results in the finances of the organization.Los programas de fidelización de clientes son una herramienta de diferen­ciación y alto impacto para crear relaciones de largo plazo con los clientes de una empresa, de tal forma que se logre una mejora en cartera y recaudo, reducción de costos de atención a clientes, incremento en ingresos por mayores ventas a los clientes más rentables, ventas cruzadas, entre muchos otros beneficios. De acuerdo con esto, se presenta un modelo de dinámica de sistemas que permita analizar los beneficios económicos, en términos de rentabilidad, que se tendrían al implementar una estrategia de fideliza­ción de clientes. Para ajustar y validar el modelo propuesto, se aplica en un caso real de una empresa comercializadora de productos agrícolas de la región. Los resultados de la simulación muestran que efectivamente el modelo cumple con su objetivo, y que el programa de fidelización logra importantes resultados en las finanzas de la organización

Rampart roads in the peat lands of Ireland: Genesis, development and current performance

The construction and improvement of roads on peat lands has always been a challenging task in geotechnical engineering. Rampart roads, which are a particular feature of the bog roads in Ireland, are caused by the excavation of peat from the roadsides over many years for use as a domestic fuel. The historical development of rampart roads and current performance under the added traffic loading is discussed. Various road improvement methods have been applied to improve the road ability to carry traffic and the technical aspects and performance of the methods are discussed. In particular, the performance of the improvement methods is related to the geotechnical properties of the underlying bog foundation

Sobre la Existencia y Unicidad de Soluciones para un Sistema de Ecuaciones No Lineal.

In this work we present an existence and uniqueness Theorem for a very especial class of a non-linear system of differential equations which include The Volterra Models.En este articulo demostraremos un teorema de existencia y unicidad para un sistema de ecuaciones lineales que incluye como consecuencia a los Modelos de Volterra

Silver-Derived Antimicrobial Coatings for the Prevention of Microbial Biofilms in Metal Pipes

The authors of this study would like to acknowledge the financial and technical support of the CETAQUA Foundation; without the said support, this work would not have been possible.The datasets generated during the current study are available from the corresponding author on reasonable requeBiodeterioration is one of the most important processes in metal pipeline corrosion, and it can be due to physical, chemical, and biological factors. Coatings rich in silver have been used to inhibit this undesirable phenomenon. In this study, the antimicrobial properties of several silver-containing products used as a coating in pipelines were determined on a pilot scale in order to evaluate the ability of silver to inhibit biofilm formation. The results showed that the coating with silver zeolite at a concentration of 2000 mg L-1 inhibited the formation of a microbial biofilm and prevented the biodeterioration process. Therefore, from our study, it can be concluded that silver zeolite shows greater protection capacity than other silver preparations and presents advantages in relation to other silver coatings that are currently availableCETAQUA Foundatio

Screening of microbial culture filtrates, plant extracts and fungicides for control of mango anthracnose

Anthracnose (Colletotrichum gloeosporioides) induces losses of up to 40% in most mango growing regions in Colombia. A series of exploratory experiments were carried out to evaluate 14 potentially antagonistic microorganisms, six plant extracts and 10 fungicides for disease control based on their ability to inhibit spore germination, mycelium growth and development of symptoms on detached fruits. In vitro experiments showed that spore germination of C. gloeosporioides was strongly inhibited (P≤0.0001) by all microbial culture filtrates, all fungicides and two plant extracts, suggesting that some of these treatments may hold promise for disease control. Similarly, all microbial filtrates, most fungicides and two plant extracts caused a significant (P≤0.0001) inhibition in mycelium growth of the pathogen. Results from this study indicated small effects of fungicides or plant extracts on anthracnose development on inoculated fruits, while microbial filtrates induced a significant reduction (P≤0.05) in lesion size. These results are very promising since current control practices rely on fungicides or costly physical treatments

Small farmers' perception of factors influencing regional chemical control of Diaphorina citri

Regional Control Areas (RCAs) have been implemented in Mexico as a strategy to delay the spread of Candidatus Liberibacter asiaticus, the causal bacterium of the disease known as Huanglongbing (HLB). The implementation of an effective management of the vector insect, Diaphorina citri in the RCAs requires the knowledge, acceptance and coordinated engagement of small agricultural producers. This research assessed the perception and knowledge of 62 citrus growers regarding the operational, sociocultural and environmental factors influencing chemical control of D. citri in four RCAs within Veracruz State. According to their responses, the following factors have been identified as the operational factors with the highest influence on the effectiveness of insecticides against D. citri within RCAs: the lack of knowledge about the use of surfactants, application speed, poor calibration of sprayers and incorrect water quality. The most significant sociocultural factors are the general unawareness of the pest and the safe and proper application of pesticides. The most relevant environmental factors during application: temperature, relative humidity, and wind speed. Sociocultural index correlated with the perception of effectiveness. Therefore, it becomes necessary to consider differences among citrus growers in each region and setting out the most appropriatestrategies for vector and disease management. Highlights Some operational practices that citrus growers are not aware of may influence their perception of chemical control. The sociocultural context of growers determines their decision-taking on insecticide applications. During the application of insecticides in regional control areas (RCAs), growers do not take into account weather conditions. The effective management of D. citri requires a coordinated engagement of small growers' in RCAs.Regional Control Areas (RCAs) have been implemented in Mexico as a strategy to delay the spread of Candidatus Liberibacter asiaticus, the causal bacterium of the disease known as Huanglongbing (HLB). The implementation of an effective management of the vector insect, Diaphorina citri in the RCAs requires the knowledge, acceptance and coordinated engagement of small agricultural producers. This research assessed the perception and knowledge of 62 citrus growers regarding the operational, sociocultural and environmental factors influencing chemical control of D. citri in four RCAs within Veracruz State. According to their responses, the following factors have been identified as the operational factors with the highest influence on the effectiveness of insecticides against D. citri within RCAs: the lack of knowledge about the use of surfactants, application speed, poor calibration of sprayers and incorrect water quality. The most significant sociocultural factors are the general unawareness of the pest and the safe and proper application of pesticides. The most relevant environmental factors during application: temperature, relative humidity, and wind speed. Sociocultural index correlated with the perception of effectiveness. Therefore, it becomes necessary to consider differences among citrus growers in each region and setting out the most appropriatestrategies for vector and disease management. Highlights Some operational practices that citrus growers are not aware of may influence their perception of chemical control. The sociocultural context of growers determines their decision-taking on insecticide applications. During the application of insecticides in regional control areas (RCAs), growers do not take into account weather conditions. The effective management of D. citri requires a coordinated engagement of small growers' in RCAs

Human-robot interaction torque estimation methods for a lower limb rehabilitation robotic system with uncertainties

Lower limb rehabilitation robot (LLRR) users, to successfully conduct isotonic exercises, require real-time feedback on the torque they exert on the robot to meet the goal of the treatment. Still, direct torque measuring is expensive, and indirect encoder-based estimation strategies, such as inverse dynamics (ID) and Nonlinear Disturbance Observers (NDO), are sensitive to Body Segment Inertial Parameters (BSIPs) uncertainties. We envision a way to minimize such parametric uncertainties. This paper proposes two human–robot interaction torque estimation methods: the Identified ID-based method (IID) and the Identified NDO-based method (INDO). Evaluating in simulation the proposal to apply, in each rehabilitation session, a sequential two-phase method: (1) An initial calibration phase will use an online parameter estimation to reduce sensitivity to BSIPs uncertainties. (2) The torque estimation phase uses the estimated parameters to obtain a better result. We conducted simulations under signal-to-noise ratio (SNR) = 40 dB and 20% BSIPs uncertainties. In addition, we compared the effectiveness with two of the best methods reported in the literature via simulation. Both proposed methods obtained the best Coefficient of Correlation, Mean Absolute Error, and Root Mean Squared Error compared to the benchmarks. Moreover, the IID and INDO fulfilled more than 72.2% and 88.9% of the requirements, respectively. In contrast, both methods reported in the literature only accomplish 27.8% and 33.3% of the requirements when using simulations under noise and BSIPs uncertainties. Therefore, this paper extends two methods reported in the literature and copes with BSIPs uncertainties without using additional sensors

La tragedia del terreno común, un arquetipo sistémico ilustrado a través del uso de la tierra en actividades agropecuarias

Los arquetipos sistémicos son estructuras genéricas que se repiten en diversos sistemas y han sido estudiados ampliamente. El estudio de los arquetipos permite la definición de políticas y estrategias encaminadas a obtener los mejores resultados de los sistemas estudiados. El arquetipo tragedia del terreno común sucede cuando ante un recurso compartido, la explotación o utilización del mismo se hace de manera individual, obteniendo los beneficios buscados, pero dado el carácter limitado del recurso, en el largo plazo se agotará de manera que ninguno de los involucrados obtenga los beneficios esperados. Se presenta aquí una aplicación del arquetipo, donde la tierra es el recurso que se consume a medida en que dos actividades, ganadería y agricultura, generan inicialmente ganancias crecientes pero que ante una sobreutilización del recurso, van disminuyendo. El sistema es modelado y simulado usando el software Vensim. De acuerdo a los resultados obtenidos, se encuentra que el comportamiento esperado teóricamente de acuerdo al arquetipo coincide con el obtenido mediante la simulación