3,791 research outputs found

    A Regional Economic Policy for Colombia

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    This paper proposes a framework for a regional economic policy in Colombia. The regional characteristics and disparities of the country are studied, and regional disparities are shown to be both significant and persistent over time. This calls for a policy initiative to promote the development of the poorer regions of the country. The studyhere draws lessons from other cases of the regional economic policy, and proposes a framework based on the regional policy initiative that is currently being implemented in Brazil.Economía regional, política regional, disparidades, convergencia

    Integrable systems with BMS3_{3} Poisson structure and the dynamics of locally flat spacetimes

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    We construct a hierarchy of integrable systems whose Poisson structure corresponds to the BMS3_{3} algebra, and then discuss its description in terms of the Riemannian geometry of locally flat spacetimes in three dimensions. The analysis is performed in terms of two-dimensional gauge fields for isl(2,R)isl(2,R). Although the algebra is not semisimple, the formulation can be carried out \`a la Drinfeld-Sokolov because it admits a nondegenerate invariant bilinear metric. The hierarchy turns out to be bi-Hamiltonian, labeled by a nonnegative integer kk, and defined through a suitable generalization of the Gelfand-Dikii polynomials. The symmetries of the hierarchy are explicitly found. For k1k\geq 1, the corresponding conserved charges span an infinite-dimensional Abelian algebra without central extensions, and they are in involution; while in the case of k=0k=0, they generate the BMS3_{3} algebra. In the special case of k=1k=1, by virtue of a suitable field redefinition and time scaling, the field equations are shown to be equivalent to a specific type of the Hirota-Satsuma coupled KdV systems. For k1k\geq 1, the hierarchy also includes the so-called perturbed KdV equations as a particular case. A wide class of analytic solutions is also explicitly constructed for a generic value of kk. Remarkably, the dynamics can be fully geometrized so as to describe the evolution of spacelike surfaces embedded in locally flat spacetimes. Indeed, General Relativity in 3D can be endowed with a suitable set of boundary conditions, so that the Einstein equations precisely reduce to the ones of the hierarchy aforementioned. The symmetries of the integrable systems then arise as diffeomorphisms that preserve the asymptotic form of the spacetime metric, and therefore, they become Noetherian. The infinite set of conserved charges is recovered from the corresponding surface integrals in the canonical approach.Comment: 34 pages, 2 figure

    Spray dried plasma as an alternative to antibiotics in piglet feeds, mode of action and biosafety

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    The use of growth promoting and therapeutic antibiotics in piglet feed has been a concerning subject over the last few decades because of the risk of generating antimicrobial resistance that could be transferred to humans. As a result, many products have been proposed as potential alternatives to the use of antibiotics, and among these, spray dried plasma is considered one of the most promising. However, there have been concerns about its biosafety, particularly during periods of emergence or re-emergence of swine diseases in different regions of the world, such as the recent porcine epidemic diarrhea virus outbreak in North America. The objectives of this paper are to review recent publications about the use of spray dried plasma as an alternative to antibiotics in weaned pig diets, the possible mechanisms of action of spray dried plasma, and the existing evidence related to the biosafety of spray dried animal plasma. Particular attention is given to studies in which spray dried plasma has been directly compared to antibiotics or other alternative antimicrobial products. Several studies on the possible modes of action for spray dried plasma, such as preservation of gut barrier function or modulation of the immune response, are also reviewed. Finally, the paper focuses on the review of the existing studies on the risks of disease transmission with the use of spray dried plasma from porcine origin. Overall, spray dried plasma is a promising alternative to in-feed antimicrobials for piglets, particularly during the early stages of the post-weaning phase. Additionally, there is enough evidence to support that commercial spray dried porcine plasma is a safe product for pigs

    Spray dried plasma as an alternative to antibiotics in piglet feeds, mode of action and biosafety

    Get PDF
    The use of growth promoting and therapeutic antibiotics in piglet feed has been a concerning subject over the last few decades because of the risk of generating antimicrobial resistance that could be transferred to humans. As a result, many products have been proposed as potential alternatives to the use of antibiotics, and among these, spray dried plasma is considered one of the most promising. However, there have been concerns about its biosafety, particularly during periods of emergence or re-emergence of swine diseases in different regions of the world, such as the recent porcine epidemic diarrhea virus outbreak in North America. The objectives of this paper are to review recent publications about the use of spray dried plasma as an alternative to antibiotics in weaned pig diets, the possible mechanisms of action of spray dried plasma, and the existing evidence related to the biosafety of spray dried animal plasma. Particular attention is given to studies in which spray dried plasma has been directly compared to antibiotics or other alternative antimicrobial products. Several studies on the possible modes of action for spray dried plasma, such as preservation of gut barrier function or modulation of the immune response, are also reviewed. Finally, the paper focuses on the review of the existing studies on the risks of disease transmission with the use of spray dried plasma from porcine origin. Overall, spray dried plasma is a promising alternative to in-feed antimicrobials for piglets, particularly during the early stages of the post-weaning phase. Additionally, there is enough evidence to support that commercial spray dried porcine plasma is a safe product for pigs.info:eu-repo/semantics/publishedVersio

    A Highly Available Cluster of Web Servers with Increased Storage Capacity

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    Ponencias de las Decimoséptimas Jornadas de Paralelismo de la Universidad de Castilla-La Mancha celebradas el 18,19 y 20 de septiembre de 2006 en AlbaceteWeb servers scalability has been traditionally solved by improving software elements or increasing hardware resources of the server machine. Another approach has been the usage of distributed architectures. In such architectures, usually, file al- location strategy has been either full replication or full distribution. In previous works we have showed that partial replication offers a good balance between storage capacity and reliability. It offers much higher storage capacity while reliability may be kept at an equivalent level of that from fully replicated solutions. In this paper we present the architectural details of Web cluster solutions adapted to partial replication. We also show that partial replication does not imply a penalty in performance over classical fully replicated architectures. For evaluation purposes we have used a simulation model under the OMNeT++ framework and we use mean service time as a performance comparison metric.Publicad

    Physical visualization of math concepts using Lego Mindstorms

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    Educational robotics has become one of the most effective methods to teach STEM concepts in a practical and didactic way at all educational level. In this context, the LEGO Mindstorms robotic platforms have been widely used due to their versatility ease of use and modularity. Despite this, most of the papers focus on K-12 and undergraduate levels, with little information reported in the literature about educational experiences at the graduate level. This article deals with the use of educational robotics for the teaching of mathematical concepts at the graduate level, and more specifically on the physical visualization of metrics (Euclidean, Taxicab, and Infinity), and the convergence of Cauchy sequence using a mobile robots LEGO Mindstorms NXT. The educational experience was applied to a group of graduate students who offered good comments on this type of educational activity and its usefulness to understand the mathematical concepts addressed. It was observed that this type of educational experiences motivates students to use mathematical concepts in interdisciplinary problems and encourages them to understand their functionality and application in the real worldPeer Reviewe

    Cognitive reserve mediates the severity of certain neuropsychological deficits related to cocaine use disorder

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    Introduction: The concept of cognitive reserve (CR) is being considered in the field of substance use disorder (SUD) by observing that there are individuals whose brain alterations are not related to the cognitive symptomatology they present. Aims: Our aims were to characterise the possible neuropsychological deficits in a sample of subjects with SUD compared to a control group and to determine whether the degree of CR is a mediator in the cognitive functioning of these patients. Methods: To perform these objectives, the study involved a sample of subjects with SUD in outpatient treatment and a control group. A CR questionnaire and a comprehensive neuropsychological assessment were administered, and we also collected data related to drug consumption and psychological well-being. Results: The SUD group showed poorer performance compared to the control group in several cognitive domains (attention, declarative memory, executive functions and emotional perception), as well as in psychological comfort. Interestingly, we observed that the deficits found in attention, declarative memory and executive functions were mediated by the CR level of the participants, an effect that we did not observe in the rest of the variables registered. Conclusion: Our results suggest that long-term drug consumption leads to cognitive deficits and affects the psychological well-being of the subjects. Moreover, the CR should be taken into account during the assessment and rehabilitation of patients with SUD due to its protective role against certain neuropsychological deficits.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Efficient integral equation formulation for inductive waveguide components with posts touching the waveguide walls

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    In this paper a surface integral equation technique is employed for the analysis of inductive waveguide problems containing metallic or dielectric objects of arbitrary shape, focusing on the case where these objects are connected to the waveguide walls. Using the extinction theorem, the main problem is split into two problems. In the first one the parallel plate waveguide Green’s functions are used. Because of the choice of these functions, the side of the object touching the waveguide wall is not considered for discretization in a method of moments analysis. The second problem is applied inside the dielectric object, and uses the free space Green’s functions. It is shown that an additional spatial image is needed to impose the proper boundary conditions for the fields on the side touching the waveguide wall in the original problem. Results show the importance of including this additional image in the formulation for the correct behavior of the fields. With the proposed technique, the paper explores some alternatives for designing specific filter responses using dielectric posts inside cavity filters. Comparisons with a commercial finite elements tool demonstrate the accuracy of the proposed integral equation formulation.This work has been developed with support from the Spanish National Project (CICYT) with Ref TEC2004-04313-C02-02/TCM, and the Regional Seneca Project with Ref 02972/PI/05

    El rol de la gestión directiva para implementar las competencias clave en las escuelas: un estudio de caso

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    Resumen basado en el de la publicaciónSe intenta analizar los efectos de un trabajo de secuenciación de las competencias clave (CCC) por los equipos directivos en: 1) la importancia para la gestión del centro, 2) la formación permanente del docente, 3) las estrategias metodológicas y evaluativas, y 4) el aprendizaje del alumnado. Todos los equipos directivos de los 30 Institutos de Educación Secundaria existentes en la ciudad de Burgos accedieron a participar. Se empleó un diseño experimental pretest-postest con grupos naturales y un procedimiento de extracción de datos mixto, cuantitativo-cualitativo. Se generaron dos grupos al azar, el A, experimental, con 16 centros, y el B, control, con 14. En el primero se llevó a cabo un trabajo de secuenciación de las CCC a lo largo de un curso escolar. El instrumento utilizado en la parte cuantitativa fue el cuestionario validado de implantación de las CCC, mientras que en la cualitativa fue un grupo de discusión con los integrantes de uno de los equipos directivos participantes. En base a los resultados, se ve positivo vincular el tratamiento de elementos curriculares como las CCC a las funciones directivas de manera secuenciada para mejorar los procesos educativos.ES

    La Actividad Física Adaptada para personas con discapacidad en España: perspectivas científicas y de aplicación actual

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    A día de hoy, seguramente nunca había sido tan socialmente reconocido el deporte para personas con discapacidad en España. El área dentro de las ciencias del deporte que se ocupa del tema es la Actividad Física Adaptada (AFA), que incluye a los deportes adaptados. Este artículo presenta el área, su desarrollo histórico y sus principales características como área de conocimiento y de desarrollo profesional, contextualizándolos dentro de la actual clasificación del Funcionamiento, la Discapacidad y la Salud (OMS, 2001). Tras ello, se analiza la evolución que ha experimentado la AFA y los deportes adaptados en relación a las áreas de investigación a nivel internacional, presentando los principales tópicos. Así mismo, las principales líneas de investigación más actuales a nivel nacional son indicadas. Son además presentadas una serie de propuestas concretas para favorecer el desarrollo de la AFA como campo de estudio multidisciplinar y como disciplina profesional. En el artículo se indican pautas concretas para el adecuado desarrollo de investigaciones en los deportes para personas con discapacidad y así mismo se detallan las actividades formativas y foros de difusión científica más relevantes sobre el área. Son indicadas a lo largo del texto sugerencias para el fomento del conocimiento y la colaboración multidisciplinar para seguir avanzando en el desarrollo de la AFA en nuestro país
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