363 research outputs found

    Modeling of RAFT polymerization processes using an efficient Monte Carlo algorithm in Julia

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    A kinetic Monte Carlo model of a RAFT process is presented. The algorithm has been developed and implemented in Julia for the three main RAFT theories under current discussion (Slow Fragmentation, Intermediate Radical Termination and Intermediate Radical Termination with Oligomers). Julia is a modern programming language designed to achieve high-performance in numerical and scientific computing. Thanks to a careful optimization of the code, it is possible to simulate a RAFT reaction scheme in short computing times for any of the three theories. The code is benchmarked against other programming languages (MATLAB, Python, FORTRAN and C), showing that Julia presents advantages for this particular system. The model offers an efficient method for predicting average properties and molecular weight distributions of the polymer species, including the bivariate MWD of the intermediate two-arm adduct. The proposed model can also be employed to obtain additional detailed information regarding the polymer microstructure at any reaction time.Fil: Pintos, Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; ArgentinaFil: Sarmoria, Claudia. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Brandolin, Adriana. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Asteasuain, Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentin

    Waterbirds from wetlands of the southeast of the Córdoba province, Argentina

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    We present a waterbird inventory corresponding to 66 wetlands in the southeast of the Province of Córdoba, Argentina. Sixty six waterbird species belonging to 16 families and eight orders were recorded. We report observations of 11 neartic migratory, seven partial migratory and one altitudinal migratory species. Records of Callonetta leucophrys, Pluvialis dominica and Limosa haemastica considered rare species for the region, were recorded in this study. Data of the relative abundance revealed 10 very abundant species, 16 abundant, 25 scarce and 12 rare, while the relative importance identified nine frequent species, 19 non-frequent and 35 occasional. This work enhances baseline knowledge of waterbirds to assist future studies in this highly threatened area with high biodiversity.Fil: Brandolin, Pablo Germán. Agrupación Amigos Para la Conservación de Las Aves; Argentina. Universidad Nacional de Río Cuarto. Facultad de Agronomía y Veterinaria. Departamento de Biología Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ávalos, Miguel Ángel. Agrupación Amigos Para la Conservación de Las Aves; ArgentinaFil: Martori, Ricardo Armando. Universidad Nacional de Río Cuarto; Argentin

    Seamount growth to be observed in future satellite gravity missions

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    Growing seamounts bear a hazard to navigation, especially if their summit reaches shallow depths and they reach the ocean surface. A seamount that expands up to the surface and creates an island, is detectable by remote sensing images, but not if the island retracts below the surface. Real time gravity observations detect the mass change independently of the optical detection, the limiting factor being only the noise level of the data acquisition in relation to the signal generated by the mass change. Starting from realistic size-frequency distributions of seamounts, we estimate the expected signals of seamount growth. We develop a method to compare the signal to the spectral noise characteristics of a GRACE-type mission, expandable to a possible mission with improved noise curve. We evaluate the expected gravity changes of seamounts and find that a noise curve of GRACE improved by a factor 10 would be sufficient to detect a realistic sea mount growth with a latency of 1 year. The detection threshold though has a tradeoff with the time resolution, since resolution improves for increased time periods over which the satellite observation can be averaged

    Evaluación mediante teledetección del efecto de canalizaciones sobre el humedal del Saladillo, Argentina

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    Los humedales son ecosistemas naturales cuya dinámica está determinada principalmente por la presencia de agua. Generalmente se los identifica como áreas que se inundan temporariamente donde el agua subterránea aflora en la superficie, o con áreas con suelos de baja permeabilidad que permanecen cubiertos por agua poco profunda. El agua, por lo tanto, juega un rol fundamental en la determinación de su estructura y funciones ecológicas. Los datos provistos por imágenes satelitales son una herramienta apropiada para analizar humedales y los cambios ocurridos en ellos a lo largo del tiempo. Los Bañados del Saladillo son un complejo de humedales en el centro de Argentina, de gran importancia para la preservación de aves acuáticas. Estos bañados han sufrido profundos cambios por el avance de la agricultura y las canalizaciones realizadas para mitigar el efecto de inundaciones en el sudeste de la provincia de Córdoba de este país. El objetivo del trabajo fue conocer la condición histórica y presente de los Bañados del Saladillo, y analizar los efectos de las canalizaciones sobre los mismos. Se estudiaron 6 imágenes satelitales que se clasificaron con ENVI 4.8 (ITT, 2010), representando la estación seca y húmeda en tres períodos: previo a las canalizaciones (1996); posterior a las canalizaciones (2004-2006); período reciente (2010-2011). Éstas fueron seleccionadas de acuerdo a las precipitaciones acumuladas en 6 meses previos para que fueran comparables. El área de lagunas se redujo entre un 70% (estación húmeda) y un 33% (estación seca). Los mayores cambios observados en la estación húmeda se reflejaron también en la reducción del número de lagunas (40%), la variabilidad de su tamaño (66%), el perímetro de las mismas (28%) y el incremento de la distancia entre ellas. Más allá de la mitigación de las inundaciones, las canalizaciones favorecieron el avance de la agricultura sobre áreas históricamente inundadas en la estación lluviosa, poniendo en riesgo la persistencia de este importante humedal del sudeste de Córdoba en el centro de Argentina. Los resultados obtenidos representan una herramienta útil al momento de tomar decisiones para el manejo y conservación de estos relictos de hábitat natural y su biodiversidad.Wetlands are natural ecosystems whose dynamics is mainly determined by the presence of water. They are generally identified as temporarily flooded areas where groundwater emerges at the surface, or areas with low permeability soils that remain covered by shallow water. The water, therefore, plays a key role in determining the structure and ecological functions of wetlands. Data provided by satellite images are an appropriate tool for analyzing wetlands and their changes over time. The Saladillo Wetlands are a complex of marshlands in the centre of Argentina, of great importance to the preservation of birds. These marshes have suffered profound changes caused by the advancement of agriculture and channels made to mitigate the effects of flooding in the southeast of the province of Cordoba in this country. The objective of our work was to know the historical and present condition of the Saladillo Wetlands, and to analyze the effects of the channelization on them. We studied six satellite images classified with ENVI 4.8. These images represented the dry and the wet season into three periods: prior to the channelization (1996), after the channelization (2004-2006); and recent period (2010- 2011). They were selected according to the accumulated rainfall during the previous 6 months to make them comparable. The pond area was reduced by 70% (wet season) and 33% (dry season). The major changes observed in the wet season also reflected in the reduction in the number of ponds (40%), the variability of their size (66%), the perimeter of flooded areas (28%) and an increasing the distance between ponds. Beyond the flood mitigation, the channelization favoured the advancement of agriculture on areas historically flooded in the rainy season, threatening the persistence of this important wetland of the southeast of Cordoba in central Argentina. Our results represent a useful tool for the management and conservation of these remnants of natural habitat and biodiversity.Fil: Lopez, C.. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; ArgentinaFil: Brandolin, Pablo Germán. Asociación Civil Amigos para la Conservación de las Aves, Córdoba; ArgentinaFil: Campanella, O. R.. Universidad Nacional de Rio Cuarto. Facultad de Cs.exactas Fisicoquimicas y Naturales. Departamento de Geologia; ArgentinaFil: Martino, A. L.. Universidad Nacional de Rio Cuarto. Facultad de Ciencias Exactas Fisicoquimicas y Naturales; ArgentinaFil: de Angelo, Carlos Daniel. Universidad Nacional de Misiones. Facultad de Ciencias Forestales. Instituto de Biologia Subtropical - Sede Puerto Iguazu; Argentin

    The risk of cancer progression in women with gynecological malignancies and thrombophilic polymorphisms: a pilot case-control study.

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    Cancer produces a hypercoagulable state, which might lead to thrombosis, and on contrary, unprovoked venous thromboembolism might be the manifestation of an occult cancer. In this pilot case-control study, we assessed the risk of gynecological malignant diseases related to the presence of the factor V Leiden and prothrombin G20210A polymorphisms. Fifty-two women underwent an operation for gynecological malignancy and were enrolled in the study. Women who underwent an operation for gynecological nonmalignant disease in the same days of cases were considered as controls. The presence of factor V Leiden and prothrombin G20210A was assessed in case and control groups. In all, 7 out of 52 cases were carriers of the 2 polymorphisms compared with 20 out of 198 controls (odds ratio = 1.3; 95% confidence interval, 0.6-3.0). The results were also similar when the risk was considered separately for the site of cancer. As for advanced and metastatic malignancies, the odds ratios were 2.3 (95% confidence interval, 0.9-6.0) and 3.3 (95% confidence interval, 1.0-11), respectively, compared to noncancer patients. When these 2 groups were compared to nonadvanced cancer group, the odds ratios for carriers of polymorphisms were 2.7 (95%confidence interval, 0.7-11.0) and 3.9 (95%confidence interval, 0.8-18.6) for advanced cancer and metastatic malignancies, respectively. Women with factor V Leiden or prothrombin G20210A polymorphisms who developed gynecological malignancy might present with a higher stage of cancer at the time of surgery. Larger case-control studies in similar cohort of patients are needed to confirm these findings

    Comunicación interna en UCIAPA: intervención institucional

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    Hemos elegido realizar nuestra práctica de comunicación en y sobre UCIAPA – Unión del Comercio la Industria y el Agro de Punta Alta-. Se trata de una entidad gremial empresaria, sin fines de lucro, con 85º años de historia en el Partido de Coronel Rosales, Sudoeste de la Provincia de Buenos Aires. Nos encontramos con el desafío de generar planes para obtener resultados y explicar –ante una Comisión Directiva– las propuestas y fundamentar nuestra intervención; principalmente, fundamentar la inversión que la entidad realizaría para llevar adelante un trabajo de planificación y gestión de la comunicación interna. Fue un desafío pensar la comunicación estratégicamente en organizaciones donde la mirada instrumental de la comunicación prima. Es por esto que, a partir de nuestra intervención y del proceso de diagnóstico, planificación y gestión que realizamos en UCIAPA, pudimos vivenciar y aprehender que: al hablar de comunicación hablamos de un proceso de negociación de sentidos vigentes en una comunidad y en un contexto determinado que requiere de revisar periódicamente los significados que conforman la cultura organizacional. El presente trabajo esperamos sea reflejo de la articulación entre teoría y práctica, además del resultado de nuestra experiencia.Facultad de Periodismo y Comunicación Socia

    Batch Emulsion Polymerization of Vinyl Chloride: Effect of Operating Variables on Reactor Performance

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    We analyze experimentally the effect of several operating conditions on conversion and molecular weight distributions of PVC obtained in batch emulsion polymerization. The operating variables studied were reaction temperature, water/monomer weight ratio, and the concentrations of initiator, emulsifier, pH regulating agent and inhibitor. We found that conversion increases with temperature and initiator concentration. It also increases with emulsifier concentration, but there is an asymptotic limit to that increase. There is an optimal water/monomer weight ratio at which the reaction rate is highest, and an optimal pH regulating agent concentration that optimizes latex quality. Average molecular weights tend to decrease slightly with conversion.Fil: Alvarez, Andrea Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Ressia, Jorge Aníbal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Aparicio, Lucrecia Vilma. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Sarmoria, Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Valles, Enrique Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Brandolin, Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentin

    Birds of a wildlife reserve in the south American pampa (Córdoba, Argentina)

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    In the Pampa ecoregion of South America, the intensification of agriculture has led to the almost total replacement of pristine vegetation by agroecosystems. This has caused a great loss of biodiversity and a decline of bird assemblages. We monitored birds in Dos Hermanas Wildlife Reserve, an integrated ecosystem-based management area in preserved natural saline wetland relicts (grasslands and shrublands) with a cultivated sector (sustainable grazing and organic crops). We recorded a total of 170 species, including altitudinal migrants, Nearctic migrants, migrants of the temperate-tropical and cold-temperate systems, and residents. Seven are globally threatened species and three are exotic species. The high diversity of birds recorded at Dos Hermanas Wildlife Reserve highlights the importance of this reserve for the conservation of the regional biota. The application of ecosystem-based management allows the presence of contrasting vegetation structures with positive effects on the diversity of bird assemblages in the Pampa region.Fil: Brandolin, Pablo Germán. Universidad Nacional de Rio Cuarto. Facultad de Agronomia y Veterinaria. Departamento de Biología Agrícola. Cátedra de Botanica Sistematica; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Ramírez, Ramiro. No especifíca;Fil: Ávalos, Miguel A.. No especifíca;Fil: Márquez, Javier Andrés. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Blendinger, Pedro Gerardo. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional; ArgentinaFil: Cantero, Juan Jose. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Departamento de Recursos Naturales. Cátedra de Microbiología Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

    La fauna silvestre de Córdoba y su rol ecológico aplicadas en prácticas socio-comunitarias de enseñanza

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    The National Rio Cuarto University (UNRC, Cordoba, Argentina) has a scheme to encourage the inclusion of community-engagement activities (PSC) in the Higher Education curriculum. In this context, the Natural Sciences department (Faculty of Exact Sciences, Physico-Chemical and Natural) carried out a PSC activity named “Animal Biodiversity”. This activity responds to specific needs by the local teaching community and the general public, where many teachers admit that they lack knowledge about the local fauna and their ecological role, and that they don’t have enough time or information to develop this type of content during their scheduled teaching sessions. Therefore, the present activity aimed to liaise the Higher Education community and local primary and secondary school teachers. Biology university students taking the “Systematic Zoology” module prepared a session about “Snakes and scorpions of Cordoba. Their identification and ecological role” that included both theoretical and practical aspects for secondary school students from “Ramón Artemio Estafolani – Granja Siquem” school. The analysis of the PSC activities highlighted the importance of building inclusion bridges with the local community, and the need to build social and cultural support networks. It is important to implement processes that encourage PSC in Higher Education, in order to highlight professional values, promote social responsibility and develop creative, active and supportive thinking. It would also provide comprehensive training of university students in ways that meet the demands and challenges of society. This work stresses the need for PSC to be continued in time by including them in our Higher Education curriculum.Fil: Dellafiore, Claudia Marisel. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; ArgentinaFil: Autrán, Valeria. Universidad Nacional de Río Cuarto. Facultad de Agronomía y Veterinaria; ArgentinaFil: Aiassa, Delia Elba. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales; ArgentinaFil: Brandolin, Pablo Germán. Universidad Nacional de Río Cuarto. Facultad de Agronomía y Veterinaria. Departamento de Biología Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Does Organic Management Help Preserve Local Functional Diversity? A Case Study In The Pampa Of South America

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    Organic agriculture is a production management system that promotes and improves the health of agroecosystems. We studied the association between changes in taxonomic diversity and changes in ecosystem functions in highly modified landscapes. We sampled birds across the land use intensification gradient from relict and organically farmed land to conventionally farmed land in the Pampa ecoregion of Argentina. Using bird traits as indicators of species’ response to environmental change or the effect of ecosystem functions, we calculate functional diversity (FD) metrics. We show a consistent change in the taxonomic and functional diversity from undisturbed habitats to agroecosystems with organic and conventional production systems. Organic farm management retains a significant amount –but not all - of birds’ functional diversity. Organic management linked with the maintenance of natural habitats could be a key to conserving ecosystem functioning
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