Modelling the inorganic nitrogen behaviour in a small Mediterranean forested catchment, Fuirosos (Catalonia)

The aim of this work was to couple a nitrogen (N) sub-model to already existent hydrological lumped (LU4-N) and semi-distributed (LU4-R-N and SD4-R-N) conceptual models, to improve our understanding of the factors and processes controlling nitrogen cycling and losses in Mediterranean catchments. The N model adopted provides a simplified conceptualization of the soil nitrogen cycle considering mineralization, nitrification, immobilization, denitrification, plant uptake, and ammonium adsorption/desorption. It also includes nitrification and denitrification in the shallow perched aquifer. We included a soil moisture threshold for all the considered soil biological processes. The results suggested that all the nitrogen processes were highly influenced by the rain episodes and that soil microbial processes occurred in pulses stimulated by soil moisture increasing after rain. Our simulation highlighted the riparian zone as a possible source of nitrate, especially after the summer drought period, but it can also act as an important sink of nitrate due to denitrification, in particular during the wettest period of the year. The riparian zone was a key element to simulate the catchment nitrate behaviour. The lumped LU4-N model (which does not include the riparian zone) could not be validated, while both the semi-distributed LU4-R-N and SD4-R-N model (which include the riparian zone) gave satisfactory results for the calibration process and acceptable results for the temporal validation process

Juifs et Phéniciens

Professeur émérite de sciences politiques à Cornell University, Martin Bernal est l’auteur de la célèbre trilogie Black Athena, qui a été partiellement traduite en français, et qui avance la thèse d’une origine à la fois égyptienne et phénicienne du « miracle grec ». Avant de consacrer plusieurs décennies à sa recherche d’élucidation des racines helléniques, Bernal travaillait principalement sur l’histoire de la Chine à l’époque moderne. Le texte que nous publions, un extrait des mémoires que..

Generation of J0 Bessel Beams with controlled spatial coherence features

An alternative method to generate J0 Bessel beams with controlled spatial partial coherence properties is introduced. Far field diffraction from a discrete number of source points on an annular region is calculated. The average for different diffracted fields produced at several rotation angles is numerically calculated and experimentally detected. Theoretical and experimental results show that for this particular case, J0 Bessel beam is a limit when the number of points tends towards infinity and the associated complex degree of coherence is also a function of the number of points.Comment: 6 pages, 5 figure

Manual de protocolo en servicio de barismo y bioseguridad

In the last 10 years, Huila has been positioning itself as the first producer of specialty coffees,surpassing departments such as Antioquia, which historically was the first producer of the grain. ElHuila is made up of 80% small producers (2 ha on average), which facilitates the detailed managementof the processes that improve quality from harvest to cup. In the municipality of Garzón, the cultivatedarea according to the SICA is 9,648.5 hectares of coffee, ranking number four of the 36coffee-producing municipalities of Huila. After the declaration of a pandemic on March 11, 2020 by theOMS, mitigation measures were decreed by various countries around the world, including Colombia. Toface and stop the speed of contagion of the virus (covid-19), mobility restrictions between cities,mandatory quarantines and closure of establishments in which there is a high capacity of people weredecreed. Such measures implied the cessation of activities of service establishments (including coffeeestablishments), and hit the economy of the entire sector, since coffee growers did not stop theirproduction, but at the end of the value chain, the customer left to consume coffee. All this made itclear that more union is needed in the sector to create strategies that boost its economy, and generatemore diffusion and trust when visiting a cafeteria and consuming its drinksEn los últimos 10 años, el Huila ha venido posicionándose como primer productor de cafés especiales,superando a departamentos como Antioquia, que históricamente se encontraba como el primerproductor del grano. El Huila está conformada en un 80% por pequeños productores (2 ha promedio),lo que facilita el manejo detallado de los procesos que mejoran la calidad, desde la recolección hastala taza. En el municipio de Garzón, el área cultivada de acuerdo con el SICA es de 9.648,5 hectáreas decafé, quedando en la posición número cuatro de los 36 municipios cafeteros del Huila. Tras ladeclaración de pandemia el 11 de marzo de 2020 por parte de la OMS, se decretaron medidas demitigación por parte de diversos países del mundo, entre ellos Colombia. Para hacer frente y detenerla velocidad de contagio del virus (covid-19), se decretaron restricciones de movilidad entre ciudades,cuarentenas obligatorias y cierre de establecimientos en los cuales se presenta un aforo elevado depersonas. Tales medidas, implicaron el cese de actividades de los establecimientos de servicios (entreellos los de café), y golpearon la economía de todo el sector, pues los caficultores no pararon suproducción, pero al final de la cadena de valor, el cliente dejó de consumir café. Todo esto puso enevidencia, que se necesita más unión del sector para crear estrategias que impulsen la economía deesté, y generen más difusión y confianza al visitar una cafetería y consumir sus bebida

Effect of calcination method and clay purity on the performance of metakaolin-based geopolymers

The calcination of kaolinite clay to produce metakaolin can be achieved using a range of processes, including rotary, fluidised bed and flash calcination. Rotary calcination was the most popular of these processes for many years as it takes place in a rotary kiln, which is readily available, at easily attainable temperatures of 650 – 800 °C. However, in recent years’ flash calcination processes have become more widely used, and the technology has advanced to a point where commercial flash metakaolin-based geopolymers are now available. Flash calcination involves the rapid heating of clay at temperatures of around 1000 °C for less than a few seconds. The differences in these calcination methods can have a notable effect on the structural ordering of the metakaolin itself, as well as playing an important role in defining the chemical and physical properties of metakaolin-based geopolymers. The purity of the clay also plays a key role in the chemistry of the geopolymers produced. Calcined clay-based geopolymers can be used as construction materials or for the immobilisation of problematic wastes, among other applications, as they can offer desirable performance characteristics. The chemical and physical properties of these geopolymers, and thus the influence of the clay source on key performance parameters, will need to be fully understood when deciding how they can be used for many different applications. This study demonstrates the effect of the calcination method on the properties of calcined metakaolin geopolymer systems for waste immobilisation applications. A main focus of this study is the rheological properties, as the flow properties of these systems are one of the most important parameters for many geopolymer applications. The porosity, heat evolution and mineralogical development of these systems is also presented, with a view towards assessing performance in targeted applications for the immobilisation of nuclear waste

Mechanical evaluation of polylactic acid (PLA) based composites reinforced with different calcium phosphates

In the present work, the mechanical performance of polylactic acid (PLA) based composites reinforced with hydroxyapatite (HA) or β-tricalcium phosphate (β-TCP) was investigated. The polymer was melt compounded with 1 and 2.5 wt% of particles by using an intensive mixer or a twin screw extruder. Morphological, thermal and rheological studies were performed to analyze the composites internal structure and filler-matrix interaction. The mechanical behavior was investigated through uniaxial tensile and quasi-static fracture tests. The different characterization techniques evidenced a better filler dispersion for composites obtained by extrusion independently of the filler used. A relatively weak filler-matrix interaction was revealed from morphological observations and rheological measurements. In addition, thermal analysis evidenced similar crystalline structure for all of the investigated materials. In general, uniaxial tensile parameters displayed almost constant values independently of the filler content or compounding method. Particularly, extruded composites with 2.5 wt% filler exhibited slightly increased ductility respect to neat PLA which was related to improved filler dispersion. The PLA matrix displayed load-displacement curves with ductile instability in quasi-static fracture tests. On the other hand, the composites with 2.5 wt% filler exhibited an increased stable crack growth followed by ductile instability. The fracture process was quantitatively described by means of critical stress intensity factor (K IQ) and strain energy release rate at propagation (G CP) parameters. The extruded composites with 2.5 wt% filler displayed improved propagation fracture toughness. Based on fractured surfaces analysis this enhanced behavior, not largely reported for untreated rigid fillers, was attributed to the effective activation of the toughening mechanisms of particle debonding and subsequent plastic void growth.Fil: Pérez, Claudio Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Eisenberg, Patricia. Instituto Nacional de Tecnología Industrial; ArgentinaFil: Bernal, Celina Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; ArgentinaFil: Perez, Ezequiel Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; Argentin

Oral History Conversation with Charlene Espinoza (Bosh Bosh)

This was an oral history conversation with Charlene Espinoza on March 28, 2017

Factores que posibilitaron la creación del Programa de Ciencia y Tecnología

El presente estudio de caso propone identificar, a partir de metodologías cualitativas, los factores que posibilitaron la creación del Programa de Ciencia y Tecnología creado el año 2006 mediante contrato de préstamo entre el gobierno del Perú y el Banco Interamericano de Desarrollo (BID) Esta metodología implicó la definición de un marco analítico para el análisis de los procesos decisionales de política pública, la entrevista a actores gubernamentales y no gubernamentales que formaron parte del proceso de creación del programa, así como la revisión de fuentes secundarias relacionada a los aspectos administrativos y legales de su creación. Posteriormente se procedió a reconstruir el proceso decisional de creación del Programa de Ciencia y Tecnología, analizar a los actores que formaron parte poniendo énfasis en sus objetivos, intereses, recursos y roles, analizar las interacciones y estrategias utilizadas y describir el contexto decisional que enmarcó el accionar de los involucrados. Los resultados permiten evidenciar que la creación del Programa de Ciencia y Tecnología resultó estar lejos de ser un proceso puramente técnico, en el que, los actores involucrados definían de la manera más racional posible, los contenidos del programa, por el contrario, se evidencia que su creación y definición de contenidos estuvo delimitada por las interacciones y estrategias motivadas por los intereses de los actores involucrados. Estas interacciones y empleo de estrategias se dieron en dos etapas, la primera comprendió el periodo 1994 - 2000, y la segunda, el periodo 2001 - 2006. Se destaca además la participación del BID que, por medio de recursos cognitivos y económicos y asumiendo el rol de promotor, aliado y experto técnico, dependiendo de la etapa del proceso decisional, contribuyó notablemente con la creación del programa. Así mismo, se evidencia que un contexto económico de crecimiento y una situación de superávit fue favorable para que se tomará la decisión de aprobar la creación del Programa de Ciencia y Tecnología.The present case study aims to identify the factors that led to the creation of the Science and Technology Program created by the loan agreement between the Government of Peru and the IDB the year 2006, on the basis of qualitative methodologies. This methodology involved the definition of an analytical framework for the analysis of decision-making processes of public policy, the interview with governmental and non-governmental actors who formed part of the process of creation of the program, as well as the review of secondary sources related to the administrative and legal aspects. It was subsequently proceeded to reconstruct the process of creation of the Science and Technology Program, analyse the actors who formed part with an emphasis on their objectives, interests, resources and roles, analyse the interactions and strategies used, and describe the decision context that framed the actions of those involved. The results allow us to demonstrate that the creation of the Science and Technology Program turned out to be far from being a purely technical process in which the actors involved defining, in the most rational way possible, the contents of the Program, on the contrary, there is evidence that its creation and definition of its content was delimited by the interactions and strategies driven by the interests of the actors involved. These interactions and employment of strategies occurred in two stages. The first covered the period 1994 - 2000, and the second the period 2001 - 2006. Further stresses the participation of the IDB, through cognitive resources and funding, and assuming the role of promoter, who is an ally and technical expert, depending on the stage of the decision-making process, contributed significantly to the creation of the program. At the same time, there is evidence that an economic context of growth and a surplus, was favorable for the decision to approve the creation of the Program.Tesi