Assessment of organic and inorganic pollution in an alluvial soil of the Riachuelo River, Buenos Aires, Argentina

Se evaluó el suelo en un área urbana a orillas del río Riachuelo, en la ciudad de Buenos Aires. Las muestras superficiales (0-25 cm) fueron tomadas en transectas perpendiculares a la costa. Se detectó la presencia de metales pesados y de compuestos orgánicos contaminantes. Los rangos de valores obtenidos para los metales fueron: 1-5 mg/kg de cadmio, 4-23 mg/kg de arsénico, 25-497 mg/kg de cobre, 8-43 mg/kg de níquel, 5-503 mg/kg de cromo y 21-235 mg/kg de plomo. El cadmio, el cobre, el arsénico y el cromo superaron los valores considerados no tolerables por la ley 24051 de residuos peligrosos para el uso más restrictivo. El tolueno fue el compuesto orgánico predominante. La concentración de metales e hidrocarburos disminuyó (aunque en diferente proporción) al alejarse unos cuatro metros desde la línea costera hacia el interior. Las variables edáficas también cambiaron sus valores en una estrecha distancia: el pH aumentó y el carbono total disminuyó entre la ribera y 4 m tierra adentro. El cinc y el cobre extraídos con DTPA (fracción que comprende a los compuestos más solubles, de mayor actividad) alcanzaron valores de 12.5-47.2 mg/kg y 2.99-14.46 mg/kg, respectivamente, muy superiores a los registrados en suelos agrícolas de origen similar. La fuente de estos metales y contaminantes orgánicos es el agua del río, y se evidencia el efecto protector de la ribera frente a la acumulación de desechos con efecto contaminante potencial. La combinación de distintos metales pesados en exceso y productos orgánicos de riesgo para la salud convierten al sitio en un lugar no apto para la recreación. La remediación o saneamiento es indispensable para minimizar los riesgos para la población que frecuenta el sitio.An evaluation of soils from a coastline sector of the Riachuelo River, in Buenos Aires City, was carried out. Superficial soil samples (0-25 cm depth) were taken on perpendicular transects from the river to inland, and analyzed to identify organic and inorganic contaminants. Ranges of values for metals were: 1-5 mg/kg for cadmium, 4-23 mg/kg for arsenic, 25-497 mg/kg for copper, 8-43 mg/kg for nickel, 5-503 mg/kg for chromium, and 21-235 mg/kg for lead. Cadmium, arsenic, copper and chromium levels were higher than those considered dangerous by the Argentine hazardous wastes law 24051. Toluene was the most important organic pollutant identified. Concentration of metals and organic pollutant decreased sharply from the coastal river line into the land. Soil characteristics also changed in a short distance: pH increased and total carbon decreased along the transect from the coast into the land. Zinc and copper extracted by DTPA reached 12.5-47.2 mg/kg and 2.99-14.46 mg/kg, respectively, higher values than those usually found in this type of soils. Metals and hydrocarbons come from the river. Four meters far from the riverside, the concentration of metals diminishes to acceptable values. This variation shows the protective effect of the riverside. Remediation to make public access possible without risk for the population is recommended

Novedades en Leucheria (Asteraceae, Mutisieae)

91-92A new variety for Leucheria diemii is described and the known area of Leucheria diemii var. diemii is extended

Becas de Verano 2014 del Instituto Balseiro – Informes

El programa de Becas de Verano del Instituto Balseiro ofrece a estudiantes universitarios avanzados o recientemente egresados de carreras de grado en Ciencias o Ingenierías la posibilidad de realizar una pasantía durante el mes de febrero. El objetivo de la misma es familiarizarse con técnicas experimentales y colaborar en tareas de investigación en laboratorios del Centro Atómico Bariloche. Anualmente, 15 estudiantes son seleccionados y reciben ayuda económica completa. Cada participante elige un único tema de investigación entre una serie de propuestas y es guiado por un grupo de investigadores del Centro Atómico Bariloche. La pasantía finaliza con la entrega de un informe y la presentación de un póster en el que se detallan los resultados obtenidos a lo largo del mes de trabajo

Radiocarbon Chronology of the Inca Expansion in Argentina

The purpose of this article is to broaden the information available on the chronology of the Inca expansion in Collasuyu by analyzing all radiocarbon dates obtained in Argentina’s Inca sites. We evaluated and classified all the dates (n=178) into three different groups (G1, G2, and G3), according to the quantity and quality of contextual information, and the possibility of effectively verifying this information through published articles. The interpretation was mainly based on the dates showing the best information regarding the origin and context of the samples (28 of the G1, and 36 of the G2). Our results indicate that the Inca advance started towards the beginnings of 15th Century AD in the northernmost part of Argentina and rapidly continued southwards, probably reaching the province of Mendoza some 50 years later. This study confirms the differences between the ethnohistoric chronology and the radiocarbon data, previously pointed out by other authors. Moreover, it suggests a sequence of at least three stages in which the Incas would have incorporated the existing territories until ca. 24°, 28°, and 34° 30' S, respectively. This is the first global study of Inca chronology in Argentina, and the first time that dates are classified to determine their level of context information and reliability.La finalidad de este artículo es contribuir al conocimiento sobre la cronología de la expansión incaica en el Collasuyu, mediante el análisis de todas las dataciones radiocarbónicas publicadas de sitios incaicos en Argentina. Evaluamos y clasificamos todas las fechas (n = 178), en tres grupos diferentes (G1, G2 y G3), de acuerdo con la cantidad y calidad de la información contextual, y con la posibilidad de verificarla, de manera efectiva, a través de los artículos publicados. La interpretación se basó principalmente en las fechas que revelan la mejor información sobre el origen y el contexto de las muestras (28 del G1 y 36 del G2). Nuestros resultados indican que el avance incaico comenzó a principios del siglo XV d. C., en el extremo norte de Argentina, y que culminó unos cincuenta años después en la provincia de Mendoza. Este estudio confirma las diferencias entre las dataciones radiocarbónicas y las fechas etnohistóricas previamente señaladas por otros autores. Además, sugiere una secuencia de al menos tres etapas en las que los incas habrían incorporado los territorios existentes hasta ca. 24°, 28° y 34° 30' S, respectivamente. Este es el primer estudio global sobre la cronología inca en Argentina, y es la primera vez que las fechas son clasificadas y utilizadas según su nivel de información, contexto y confiabilidad.O objetivo deste artigo é contribuir para o conhecimento da cronologia da expansão inca no Collasuyu, analisando todas as datações de radiocarbono publicadas de sítios incas na Argentina. Avaliamos e classificamos todas as datas (n = 178) em três grupos distintos (G1, G2 e G3) de acordo com a quantidade e qualidade das informações contextuais e com a possibilidade de sua verificação efetiva pelos artigos publicados. A interpretação baseou-se principalmente nas datas que apresentam as melhores informações sobre a origem e contexto das amostras (28 do G1 e 36 do G2). Nossos resultados indicam que o avanço inca começou no início do século XV d.C., no extremo norte da Argentina e culminou cerca de 50 anos depois na província de Mendoza. Este estudo confirma as diferenças entre a datação por radiocarbono e datas etno-históricas, previamente indicadas por outros autores. Além disso, sugere uma sequência de pelo menos três etapas nas quais os Incas teriam incorporado os territórios existentes até ca. 24°, 28° e 34° 30' S, respectivamente. Este é o primeiro estudo global da cronologia inca na Argentina e é a primeira vez que as datas são classificadas e utilizadas de acordo com seu nível de informação de contexto e confiabilidade.Facultad de Ciencias Naturales y Muse

Effects of pre‐operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study

We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05-1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4-7 days or >= 8 days of 1.25 (1.04-1.48), p = 0.015 and 1.31 (1.11-1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care