How concerted are ionic hops in inorganic solid-state electrolytes?

Despite being fundamental to the understanding of solid-state electrolytes (SSE), little is known on the degree of coordination between mobile ions in diffusive events. Thus far, identification of concerted ionic hops mostly has relied on the analysis of spatio-temporal pair correlation functions obtained from atomistic molecular dynamics (MD) simulations. However, this type of analysis neither allows for quantifying particle correlations beyond two body nor determining concerted ionic hop mechanisms, thus hindering a detailed comprehension and possible rational design of SSE. Here, we introduce an unsupervised k-means clustering approach able to identify ion-hopping events and correlations between many mobile ions, and apply it to a comprehensive ab initio MD database comprising several families of inorganic SSE and millions of ionic configurations. It is found that despite two-body interactions between mobile ions are largest, higher-order $n$-ion ($2 < n$) correlations are most frequent. Specifically, we prove an universal exponential decaying law for the probability density function governing the number of concerted mobile ions. For the particular case of Li-based SSE, it is shown that the average number of correlated mobile ions amounts to $10 \pm 5$ and that this result is practically independent of temperature. Interestingly, our data-driven analysis reveals that fast-ion diffusion strongly and positively correlates with ample hopping lengths and long hopping spans but not with high hopping frequencies and short interstitial residence times. Finally, it is shown that neglection of many-ion correlations generally leads to a modest overestimation of the hopping frequency that roughly is proportional to the average number of correlated mobile ions.Comment: 12 pages, 7 figure

The Use of Ash From Waste Water Treatment Sludge as a Mineral Addition in the Cement Industry

Los lodos producidos en las plantas de tratamiento de agua residuales (TAR) son elementos patógenos y metales nocivos descargados y gran cantidad de sólidos en suspensión, lo que eventualmente hace que el cuerpo de agua se acumule. El estudio investigó la posibilidad de utilizar lodos de TAR como adición mineral, para lo cual se determinó la reactividad con cemento Portland, analizándose el material a diferentes temperaturas de calcinación y tiempos de residencia. Las muestras con mejores resultados se utilizaron para investigar el desempeño de mezclas de concreto en las que se sustituyó el lodo de TAR por cemento Portland en concentraciones del 5% al 30% en tres proporciones diferentes de agua / aglutinante (p / b) (0,35, 0,50 y 0,65). Los resultados indican que el uso de cenizas de lodo TAR mejora la resistencia de las mezclas de concreto siendo su uso posible para obtener la misma resistencia de una mezcla de hormigón con cemento Portland 100% y reducir el consumo de cemento en 37-200 kg / m3 de hormigón, dependiendo de la concentración de sustitución y el nivel de resistencia deseado

Snakes based tracking and texture analysis of microscopic images

Comunicación presentada en el VII Symposium Nacional de Reconocimiento de Formas y Análisis de Imágenes, SNRFAI, Barcelona, abril 1997.Snake based tracking over a textured potential is applied to recover the 3D structure of a complex organ, the eye, from a sequence of slices. Grey level images are first analysed by a probabilistic method to derive a suitable potential. Then, the snake is initialised by hand and, finally, its energy function is minimised. Temporal discontinuity problems due to the nature of the images (microscopic slices tinted and taken by hand) are solved

Dinámica estacional de la ictiofauna de Laguna Alsina, provincia de Buenos Aaires, Argentina

This study aims at characterizing the seasonal dynamics of the ichtyofauna of Alsina lagoon which belongs to the Encadenadas del Oeste (Province of Buenos Aires, Argentina). Fish sampling was performed on a three-month basis, from April 2007 to March 2008, using gill nets and a trawl net. Diversity (H’) and species richness were calculated for every sampling station and for each season. Differences in H´ values were analyzed via ANOVA. Relative abundance in number was estimated with net mesh capture. Capture per unit effort (CPUE) was calculated considering the fishing night as unit effort and the size structure of the dominant species was described. A total of 8643 individuals belonging to 14 species were captured. Species richness varied from 8 to 11. H´ evidenced no significant differences among places (p=0.15) although differences were recorded all over the year (p=0.001). H´ was highest in autumn (2.23) and lowest in spring (0.96). In autumn, the dominant species were Odontesthes bonariensis (34%), Parapimelodus valenciennis (32%) and Oligosarcus jenynsii (28%). In winter, the dominant species were only O. bonariensis and O. jenynsii, both representing more than 90%. A significant increase in CPUE was observed in pejerrey (O. bonariensis). Dominant size ranges were 15-17 and 20-25 cm Lst in O. bonariensis and 17-23 cm Lst in O. jenynsii. It can thus be concluded that Alsina lagoon has a key role as a biodiversity reservoir of continental waters. The ichthyc community has undergone modifications, of which the most relevant include: disappearance of P. valenciennis and increase of O. bonariensis. The recuperation of O. bonariensis stock therefore guarantees a promissing future for this environment which formerly reached highest productivity in Encadenadas del Oeste system.This study aims at characterizing the seasonal dynamics of the ichtyofauna of Alsina lagoon which belongs to the Encadenadas del Oeste (Province of Buenos Aires, Argentina). Fish sampling was performed on a three-month basis, from April 2007 to March 2008, using gill nets and a trawl net. Diversity (H’) and species richness were calculated for every sampling station and for each season. Differences in H´ values were analyzed via ANOVA. Relative abundance in number was estimated with net mesh capture. Capture per unit effort (CPUE) was calculated considering the fishing night as unit effort and the size structure of the dominant species was described. A total of 8643 individuals belonging to 14 species were captured. Species richness varied from 8 to 11. H´ evidenced no significant differences among places (p=0.15) although differences were recorded all over the year (p=0.001). H´ was highest in autumn (2.23) and lowest in spring (0.96). In autumn, the dominant species were Odontesthes bonariensis (34%), Parapimelodus valenciennis (32%) and Oligosarcus jenynsii (28%). In winter, the dominant species were only O. bonariensis and O. jenynsii, both representing more than 90%. A significant increase in CPUE was observed in pejerrey (O. bonariensis). Dominant size ranges were 15-17 and 20-25 cm Lst in O. bonariensis and 17-23 cm Lst in O. jenynsii. It can thus be concluded that Alsina lagoon has a key role as a biodiversity reservoir of continental waters. The ichthyc community has undergone modifications, of which the most relevant include: disappearance of P. valenciennis and increase of O. bonariensis. The recuperation of O. bonariensis stock therefore guarantees a promissing future for this environment which formerly reached highest productivity in Encadenadas del Oeste system

Ecología trófica del pejerrey (Odontesthes bonariensis) en la laguna del Venado y Alsina, dos ambientes del sistema encadenadas del oeste, Prov. de Buenos Aires

The aim of the present study was to analyze the feeding of the silverside Odontesthes bonariensis in the Venado and Alsina lake, which are part of the Encadenadas del Oeste lake system. The stomach content of 206 individuals was analyzed. Total length ranged from 93 to 585 mm. The vacuity index (VI) and repletion index (RI) were estimated by season and site. Index of Relative Importance (IRI) for each food category and the trophic level (TL) of pejerrey were calculated by site. The diet of the silverside was composed of 68 prey items, most of which were occasional preys. Copepods and cladocerans were the main prey items in the diet in both lagoons. Copepods were the most important item in Venado lagoon and cladocerans were so in Alsina lagoon. The micro crustaceans were the main prey item for both size classes, however their %IRI decreased in the larger fish (95% IRI for the 93-299 mm Tl size class and 63% IRI for the 300-585 mm Tl size class). Silverside TL estimated for each lagoon (TL= 3) characterizes it as secondary consumer.El objetivo del presente estudio fue analizar la alimentación del pejerrey, Odontesthes bonariensis, en las lagunas del Venado y Alsina, que forman parte del sistema de lagunas encadenadas del oeste. Se analizó el contenido estomacal de 206 individuos. La longitud total osciló entre 93 y 585 mm. El índice de vacuidad (VI) y el índice de repleción (RI) se estimaron por temporada y sitio. El índice de importancia relativa (IRI) para cada categoría de alimentos y el nivel trófico (TL) de pejerrey se calcularon por sitio. La dieta del pejerrey estuvo compuesta por 68 presas, la mayoría de las cuales eran presas ocasionales. En ambas lagunas copépodos y cladóceros fueron los principales presas en la dieta. Los copépodos fueron el elemento más importante en la laguna de Venado y los cladóceros en la laguna Alsina. Los micro crustáceos fueron la presa principal para ambas clases de tamaño, sin embargo, su porcentaje de IRI disminuyó en los peces más grandes (95% de IRI para la clase de tamaño de 93-299 mm Tl y 63% de IRI para la clase de tamaño de 300-585 mm Tl). El TL estimado para el pejerrey de cada laguna (TL = 3) lo caracteriza como consumidor secundario

Resultado de diferentes medidas de manejo tendientes a optimizar la pesquería de pejerrey (Odontesthes bonariensis) en la laguna Cochicó, Argentina

The Cochicó shallow lake is part of the Encadenadas del Oeste system (Buenos Aires province, Argentina). Since 2000, the municipal state has been conducting intensive tasks to supplement silverside (Odontesthes bonariensis) fisheries stock by seeding and furtive fishing control, as part of the strategy to improve and protect the resource, in order to achieve a progressive increase of the silverside stock and quality. The aim of this study was to evaluate the silverside population of the Cochicó shallow lake and, consequently, the management policies that are being implemented on this resource. Sampling was performed on a three-month basis, from April 2007 to March 2008, using gillnets and a trawl net. The relative abundance in number was estimated with gillnet capture. Catch per unit effort (CPUE) in weight was calculated considering the fishing night as the unit effort. The size structure of the dominant species was described and the proportional stock density index (PSD) was calculated. Odontesthes bonariensis was the dominant species, with a relative abundance of more than 92%. The mean CPUE was 201.6 kg/night. This value was higher than that found in previous years (19 to 120 kg/night) using the same methodology. The dominant size ranges were 25-27 and 29-31 cm total length (Lt). The PSD were 71% and 40% for sizes with potential recreational and commercial fishing harvest, respectively. The current quality and abundance of this fishing resource is essential for the Cochicó shallow lake and is the reason why it has emerged as one of the most prestigious silverside recreational fisheries locations in Argentina.La laguna&nbsp; Cochicó es parte del sistema Encadenadas del Oeste (provincia de Buenos Aires, Argentina). Desde el año 2000, el estado municipal ha estado realizando tareas intensivas para complementar el stock pesquero del pejerrey (Odontesthes bonariensis) mediante la siembra y el control de la pesca furtiva, como parte de la estrategia para mejorar y proteger el recurso, a fin de lograr un aumento progresivo del stock de pejerrey y su calidad. El objetivo de este estudio fue evaluar la población de pejerrey de la laguna Cochicó y, en consecuencia, las políticas de manejo que se están implementando en este recurso. El muestreo se realizó durante tres meses, de abril de 2007 a marzo de 2008, utilizando redes de enmalle y una red de arrastre. La abundancia relativa en número se estimó con la captura de redes de enmalle. La captura por unidad de esfuerzo (CPUE) en peso se calculó considerando la noche de pesca como la unidad de esfuerzo. Se describió la estructura de tamaño de la especie dominante y se calculó el índice de densidad de población proporcional (PSD). Odontesthes bonariensis fue la especie dominante, con una abundancia relativa de más del 92%. La CPUE media fue de 201.6 kg / noche. Este valor fue mayor que el encontrado en años anteriores (19 a 120 kg / noche) utilizando la misma metodología. Los rangos de tamaño dominantes fueron 25-27 y 29-31 cm de longitud total (Lt). Los PSD fueron 71% y 40% para tallas con potencial de pesca recreativa y comercial, respectivamente. La calidad y abundancia actual de este recurso de pesca es esencial para la laguna Cochicó y es la razón por la que se ha convertido en uno de los lugares de pesca recreativa más prestigiosos de la Argentina

Resultado de diferentes medidas de manejo tendientes a optimizar la pesquería de pejerrey (Odontesthes bonariensis) en la laguna Cochicó, Argentina

The Cochicó shallow lake is part of the Encadenadas del Oeste system (Buenos Aires province, Argentina). Since 2000, the municipal state has been conducting intensive tasks to supplement silverside (Odontesthes bonariensis) fisheries stock by seeding and furtive fishing control, as part of the strategy to improve and protect the resource, in order to achieve a progressive increase of the silverside stock and quality. The aim of this study was to evaluate the silverside population of the Cochicó shallow lake and, consequently, the management policies that are being implemented on this resource. Sampling was performed on a three-month basis, from April 2007 to March 2008, using gillnets and a trawl net. The relative abundance in number was estimated with gillnet capture. Catch per unit effort (CPUE) in weight was calculated considering the fishing night as the unit effort. The size structure of the dominant species was described and the proportional stock density index (PSD) was calculated. Odontesthes bonariensis was the dominant species, with a relative abundance of more than 92%. The mean CPUE was 201.6 kg/night. This value was higher than that found in previous years (19 to 120 kg/night) using the same methodology. The dominant size ranges were 25-27 and 29-31 cm total length (Lt). The PSD were 71% and 40% for sizes with potential recreational and commercial fishing harvest, respectively. The current quality and abundance of this fishing resource is essential for the Cochicó shallow lake and is the reason why it has emerged as one of the most prestigious silverside recreational fisheries locations in Argentina.Instituto de Limnología "Raúl A. Ringuelet

Ecología trófica del pejerrey (<i>Odontotesthes bonariensis</i>) en la laguna del Venado y Alsina, dos ambientes del sistema Encadenadas del Oeste, prov. de Buenos Aires

The aim of the present study was to analyze the feeding of the silverside Odontesthes bonariensis in the Venado and Alsina lake. which are part of the Encadenadas del Oeste lake system. The stomach content of 206 individuals was analyzed. Total length ranged from 93 to 585 mm. The vacuity index (VI) and repletion index (RI) were estimated by season and site. Index of Relative Importance (IRI) for each food category and the trophic level (TL) of pejerrey were calculated by site. The diet of the silverside was composed of 68 prey items, most of which were occasional preys. Copepods and cladocerans were the main prey items in the diet in both lagoons. Copepods were the most important item in Venado lagoon and cladocerans were so in Alsina lagoon. The micro crustaceans were the main prey item for both size classes, however their %IRI decreased in the larger fish (95% IRI for the 93-299 mm Tl size class and 63% IRI for the 300-585 mm Tl size class). Silverside TL estimated for each lagoon (TL= 3) characterizes it as secondary consumer.Facultad de Ciencias Naturales y Muse

Caracterización de la ictiofauna en la Laguna del Monte, provincia de Buenos Aires

The purpose of this study was to describe as well as to characterize the fish populations living in Del Monte lagoon, which belongs to the Encadenadas del Oeste system in the province of Buenos Aires, Argentina. This research was carried out using trammel nets with meshes of six different sizes at three sampling stations during October 2003. The species captured in the area of study were firstly identified. The specific diversity of each fishing site was subsequently estimated. In addition, sex ratio, size structure, and the relative abundance both in number and weight were also determined for each species. Total capture included 647 individuals, which corresponded to the following six species: mojarra Astyanax eigenmanniorum, dientudo Oligosarcus jenynsii, pejerrey Odontesthes bonariensis, carp Cyprinus carpio, sabalito Cyphocharax voga, and catfish Rhamdia quelen. The specific diversity was very similar at the three sampling stations. The mojarra Astyanax eigenmanniorum evidenced the highest relative abundance in number, it was followed by the dientudo Oligosarcus jenynsii and the pejerrey Odontesthes bonariensis. The highest ichthyomass corresponded to the carp Cyprinus carpio. The entrance of the latter to the Del Monte lagoon was corroborated, the highest number of samples was recorded near the outlet of Guaminí and Malleo-Leufú brooks. A marked decrease in the abundance of the pejerrey Odontesthes bonariensis as well as an increase in the number of the dientudo Oligosarcus jenynsii and the mojarra Astyanax eigenmanniorum were also observed.The purpose of this study was to describe as well as to characterize the fish populations living in Del Monte lagoon, which belongs to the Encadenadas del Oeste system in the province of Buenos Aires, Argentina. This research was carried out using trammel nets with meshes of six different sizes at three sampling stations during October 2003. The species captured in the area of study were firstly identified. The specific diversity of each fishing site was subsequently estimated. In addition, sex ratio, size structure, and the relative abundance both in number and weight were also determined for each species. Total capture included 647 individuals, which corresponded to the following six species: mojarra Astyanax eigenmanniorum, dientudo Oligosarcus jenynsii, pejerrey Odontesthes bonariensis, carp Cyprinus carpio, sabalito Cyphocharax voga, and catfish Rhamdia quelen. The specific diversity was very similar at the three sampling stations. The mojarra Astyanax eigenmanniorum evidenced the highest relative abundance in number, it was followed by the dientudo Oligosarcus jenynsii and the pejerrey Odontesthes bonariensis. The highest ichthyomass corresponded to the carp Cyprinus carpio. The entrance of the latter to the Del Monte lagoon was corroborated, the highest number of samples was recorded near the outlet of Guaminí and Malleo-Leufú brooks. A marked decrease in the abundance of the pejerrey Odontesthes bonariensis as well as an increase in the number of the dientudo Oligosarcus jenynsii and the mojarra Astyanax eigenmanniorum were also observed