Communication tree problems

In this paper, we consider random communication requirements and several cost measures for a particular model of tree routing on a complete network. First we show that a random tree does not give any approximation. Then give approximation algorithms for the case for two random models of requirements.Postprint (published version

Concentración de metanol en nafta reformulada con metanol como antidetonante

Los primeros antidetonantes utilizados en las naftas fueron el MMT y el plomo tetra etilo. Sin embargo, la emisión de plomo a la atmosfera genera serios problemas a la salud pública. Para la eventual eliminación de Plomo incremento el uso de otros componentes producidos en las refinerías por este proceso, tales como BTX. En la actualidad por estudios ambientales se comienza a utilizar alcoholes. En el presente trabajo se estudia el Metanol como antidetonante de una nafta reformulada. Por ello, se estudia el ELL del sistema ternario Metanol + Tolueno + Hexano. Los datos experimentales de líneas de unión del sistema ternario se obtuvieron a 278.15, 283.15, 288.15 y 293.15 K. Se graficaron los datos experimentales obteniéndose las curvas binodales para las distintas temperaturas. Los resultados experimentales muestran que la solubilidad aumenta conforme aumenta la temperatura.The first anti-detonating used in naphtha were MMT and tetra ethyl lead. Nevertheless, the emission of lead to the atmosphere generates serious problems to the public health. For the eventual elimination of Lead increased the use of other components produced in the refineries by this process, such as BTX. At the present time by environmental studies is begun to use alcohols. In the present work the methanol is studied like anti-detonating additive of reformulated naphtha. Therefore, the ELL of the ternary system Methanol + Toluene + Hexane is studied. The experimental data of ternary system tie lines were obtained at 278.15, 283.15, 288.15 and 293.15 K. The experimental data were plotted, obtaining the binodal curves for the different temperatures. The experimental results show that the solubility increases as the temperature increases.Fil: Veliz, Jonatán H.. Consejo Nacional de Investigaciones Científicas y TécnicasFil: Cases, Alicia M.. Consejo Nacional de Investigaciones Científicas y TécnicasFil: Gramajo, Monica B.. Consejo Nacional de Investigaciones Científicas y Técnica

Public health competencies and contents in Spanish university degree programmes of Veterinary Medicine

Objetivo: Consensuar las competencias profesionales de salud pública que deben adquirir los/las estudiantes en el Grado en Veterinaria y los contenidos fundamentales que deben incluir los programas de salud pública según el criterio de docentes de salud pública del Grado en Veterinaria representantes de distintas universidades españolas. Métodos: Se organizó la 3 ª Reunión del Foro de Profesorado Universitario de Salud Pública en la Facultad de Veterinaria de la Universidad de Córdoba (12-13 de enero de 2016). Participaron 42 docentes de nueve universidades españolas con Grado en Veterinaria y se distribuyeron en cinco grupos durante tres sesiones de trabajo para identificar y clasificar las competencias propias del grado, proponer contenidos de salud pública para las competencias identificadas, y organizar los contenidos en bloques temáticos. Los resultados se discutieron en distintas sesiones plenarias hasta alcanzar acuerdos. Resultados: El mayor número de competencias identificadas corresponde a actividades de las funciones «Valorar las necesidades de salud de la población» y «Desarrollar políticas de salud». El programa resultante incluye contenidos básicos organizados en cinco bloques: 1) Fundamentos de salud pública; 2) Estudio e investigación en salud pública; 3) Producción, sanidad animal y medio ambiente; 4) Seguridad alimentaria; y 5) Educación sanitaria y comunicación. Conclusiones: Los acuerdos alcanzados pueden ser un buen punto de partida para orientar una propuesta formativa en salud pública del grado para los futuros profesionales de veterinaria.Objective: To reach a consensus among public health faculty from various Spanish universities about the core public health competencies that should be integrated into the Veterinary Medicine degree training. Methods: The 3 rd Forum of University Professors of Public Health was held at the School of Veterinary Medicine of the University of Cordoba (12-13 January 2016). Forty-two university professors and lecturers from nine Spanish universities with veterinary degrees participated in the forum. They were divided into five working groups during three working sessions to identify and classify core public health competencies for the Veterinary Medicine degree, propose public health contents for the identified competencies and organize such contents in thematic blocks. The results were discussed in different plenary sessions. Results: The highest number of core competencies was identified in the activities related to the following public health functions: «Assessment of the population's health needs» and «Developing health policies». The final programme included basic contents organized into five units: 1) Fundamentals of public health; 2) Study and research in public health; 3) Production, animal health and environment; 4) Food security; and 5) Health education. Conclusions: The public health core competencies and contents identified in this Forum may be considered as a starting point to update public health training programmes for future veterinary professionals

Algunos ejemplos de relación entre agregación, capacidad de infiltración y erosión en suelos mediterráneos

[Resumen] Este trabajo tiene por objeto evaluar la influencia de la agregación sobre la capacidad de infiltración y la tendencia a la erosión de suelos mediterráneos sobre litología caliza. Se identifican algunas variables de agregación que influyen de una manera importante en la infiltración y la erosión, aunque es en combinación con otras características del suelo cuando estas variables explican mejor dichos parámetros. Se consiguen una serie de modelos de ecuaciones de regresión múltiple basadas en variables indicadoras de la agregación de los suelos y otras características (cobertura vegetal, materia orgánica, pedregosidad y humedad del suelo) que explican bastante bien la capacidad de infiltración, la concentración de sedimentos y la erosión de los suelos en las zonas de estudio.[Abstract] The objective of this work is to evaluate the influence of soil aggregation on soil infiltration capacity and erosion in mediterranean soils developed on limestones. Sorne key-variables related to soil aggregation which play an important role on soil infiltration capacity and erosion are identified. Especially the combination of these variables with other soil characterisitics give the most satisfactory results explaining soil infiltration and erosiono Sorne models of multiple regression equations based in variables related to aggregation and other soil characteristics (vegetation cover, organic matter, stoniness and soil moisture) are obtained. They explain quite well the infiltration capacity, the sediment concentration and the erosion in the study zones

Influencia de la estructura y usos del suelo en las características de retención hídrica de suelos mediterráneos sobre litología caliza

[Resumen] Se investigan las diferencias entre la capacidad de retención hídrica de suelos mediterráneos sobre litología caliza sometidos a diferentes usos: incendiados y bajo pastoreo intensivo. En estos mismos suelos se valoran las relaciones entre estructura del suelo y capacidad de retención hídrica a diversos puntos de la curva de retención. Agregados de pequeño tamaño y materia orgánica influyen positivamente y de manera considerable en la capacidad de retención en casi todos los puntos de la curva de retención determinados. Agregados de gran tamaño y microagregados estables en agua influyen negativamente. La combinación de agregados de tamaño 1-0,105 mm y el contenido en materia orgánica predicen bastante bien la capacidad de retención a niveles bajos de succión (pF 0,4 YpF 1).[Abstract] The differences between the water holding capacity of Mediterranean soils developed on limestones and under different land uses (burnt and overgrazed soils) are investigated. The relationships between soil structure and soil moisture characteristic at different levels of the water retention curve in these same soils are evaluated. Organic matter and small sized aggregates are positively related to the water holding capacity. Large sized aggregates and waterstable microaggregates are negatively related to the water holding capacity of the soils. The combination of aggregates at 1-0,105 mm and organic matter content predict quite well the water retention capacity at lower suction levels (pF 0,4 and pF 1)

Graphene-based materials for the electrochemical determination of hazardous ions

[EN] The use of graphene in the field of electrochemical sensors is increasing due to two main properties that make graphene and derivatives appealing for this purpose: their conductivity and high surface area. In addition, graphene materials can be easily functionalized with nanoparticles (Au, Pt, etc.) or organic molecules (DNA, polymers, etc.) producing synergies that allow higher sensitivity, lower limit of detection as well as increased selectivity. The present review focuses on the most important works published related to graphene-based electrochemical sensors for the determination of hazardous ions (such as As(III), Cd2+, Pb2+, Hg2+, Cr(VI), Cu2+, Ag+, etc.). The review presents examples of the use of graphene-based electrodes for this purpose as well as important parameters of the sensors such as: limit of detection, linear range, sensitivity, main interferences, stability, and reproducibility. The application of these graphene-based electrodes in real samples (water or food matrices) is indicated, as well. There is room for improvement of these type of sensors and more effort should be devoted to the use of doped graphene (doped for instance with N, B, S, Se, etc.) since electrochemically active sites originated by doping facilitate charge transfer, adsorption and activation of analytes, and fixation of functional moieties/molecules. This will allow the sensitivity and the selectivity of the electrodes to be increased when combined with other materials (nanoparticles/organic molecules). © 2016 Elsevier B.V. All rights reserved.J. Molina and F. Cases wish to thank to the Spanish Ministerio de Ciencia e Innovacion (contract MAT2016-77742-C2-1-P) for the financial support. J. Molina is grateful to the Conselleria d'Educacio, Formacio i Ocupacio (Generalitat Valenciana) for the Programa VALi+D Postdoctoral Fellowship (APOSTD/2013/056). Tim Vickers is gratefully acknowledged for help with the English revision.Molina Puerto, J.; Cases Iborra, FJ.; Moretto, LM. (2016). Graphene-based materials for the electrochemical determination of hazardous ions. Analytica Chimica Acta. 946:9-39. https://doi.org/10.1016/j.aca.2016.10.019S93994

Simulation Approach for Timing Analysis of Genetic Logic Circuits

Constructing genetic logic circuits is an application of synthetic biology in which parts of the DNA of a living cell are engineered to perform a dedicated Boolean function triggered by an appropriate concentration of certain proteins or by different genetic components. These logic circuits work in a manner similar to electronic logic circuits, but they are much more stochastic and hence much harder to characterize. In this article, we introduce an approach to analyze the threshold value and timing of genetic logic circuits. We show how this approach can be used to analyze the timing behavior of single and cascaded genetic logic circuits. We further analyze the timing sensitivity of circuits by varying the degradation rates and concentrations. Our approach can be used not only to characterize the timing behavior but also to analyze the timing constraints of cascaded genetic logic circuits, a capability that we believe will be important for design automation in synthetic biology