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Riparian areas of riverine plains develop extensive floodable areas named riverine wetlands, which are essential to the water cycle balance and ecosystem dynamics. In this study, we contrasted the hydrological and physicochemical variables of riverine wetlands of both peri-urban areas impacted by intensive farming and those of rural areas with the indicators of the biotic structure (taxonomic richness, Shannon diversity and total density) of benthic diatoms, phytoplankton, zooplankton, macroinvertebrates, chironomids, fishes, turtles, and birds. The study was performed on riverine waters of the Pampean plain, Argentina, with four seasonal samplings conducted in 2017–2018. Our results showed that the significant deepening of the groundwater level caused by aquifer overexploitation in peri-urban areas, as well as the declining surface water quality with higher phosphorus and total nitrogen concentrations, affected the taxonomic richness, diversity, and total density of the biotic assemblages of riverine wetlands. The taxonomic richness of birds, turtles, phytoplankton, chironomids, and fishes was the most sensitive to land use. Phytoplankton, chironomid, and fish diversity showed the greatest differences between rural and peri-urban riverine waters, while the total density of chironomids and birds showed the greatest differences according to land use. The results suggest that the socioeconomic development in those riverine wetlands that still maintain conditions close to the natural ones needs to be subject to guidelines derived from integrated basin management and sustainable urban planning.

Background: Suicide and suicide attempts are impacting events for patients and their relatives, and these behaviors are still taboo among adults and may be even more traumatic when involving children and adolescents. Aim: In this study we aimed to describe suicide rates among children and adolescents in Paraguay over the last decades as well as associated factors such as sociodemographic characteristics and methods used for suicide. Methods: This was an observational and exploratory study describing the frequency and characteristics of suicide among children and adolescents in Paraguay between 2004 and 2022. Official records of all deaths by suicide were reviewed, and statistical analyses were performed. In addition, an attempt was made to predict the number of suicides in the next 5 years using a mathematical model based on simple linear regression. Results: In the 18-year period observed, 940 suicides among children and adolescents were recorded. The mean age was 15.05 ± 1.8 years old. Of these, 51.17% were male, 74.6% were from urban areas, and 22.2% were from the Greater Asunción and Central Department of Paraguay. The most frequently used method of suicide was intentional self-inflicted injury by hanging, strangulation, or suffocation, which all represented 75.3% of the cases. Our mathematical modeling based on simple linear regression determined that the expected yearly number of national suicides in the pediatric population for the following years, from 2023 to 2027, will range between 72 and 81. Conclusion: This study is the first large national epidemiological report on the emerging issue of suicide among children and adolescents in Paraguay. It may be a relevant source of information for mental health professionals, health authorities, and decision makers to develop national prevention strategies and actions against suicide among youths.

Los bañados de desborde fluvial (BDF) abarcan tramos (cientos de metros a kilómetros) de los sistemas fluviales pampeanos, con características y funciones particulares. Estos humedales se originan por un afloramiento del nivel freático y una disminución local del gradiente hidráulico, lo que da lugar a un ensanchamiento del curso de agua principal y la aparición de una red de microdrenaje que acompaña a este último. Estas condiciones favorecen el desarrollo de humedales asociados al curso principal, con un importante desarrollo de la vegetación característica de suelos muy húmedos. El objetivo de este trabajo fue el de analizar las características hidrológicas y la calidad del agua de los BDF en zonas urbanizadas con actividad agrícola (localizados en los arroyos Carnaval y Del Gato) y en zonas rurales con ganadería extensiva (ubicados en los arroyos Cajaravillas y Chubichaminí), del NE de la provincia de Buenos Aires, con el fin de reconocer cómo los diferentes usos del suelo modifican las condiciones de conservación de los humedales. Los análisis geohidrológicos se realizaron a escala regional (cuenca), semi-detalle (subcuenca) y detallada (BDF). Los resultados mostraron que la sobreexplotación de las aguas subterráneas afecta a la permanencia del agua en los humedales, debido a la desconexión entre el nivel freático y el nivel basal de los BDF situados en las zonas urbanizadas con actividad agrícola. En estos últimos se ha observado también que el aporte de nutrientes contribuye significativamente al deterioro de la calidad del agua. La conclusión es que un diagnóstico ambiental de estos BDF requiere un enfoque regional de los procesos hidrológicos para adoptar acciones adecuadas para su conservación., The riverine wetlands (RWs) cover stretches (ranging from hundreds of meters to kilometers) of the Pampean river systems, with particular characteristics and functions. These wetlands are the result of an outcropping of the phreatic level and a local decrease in the hydraulic gradient, which gives rise to a widening of the main watercourse together with the appearance of a micro-drainage network. These conditions favor the development of wetlands associated with the main course, with a significant development of the typical vegetation of very wet soils. The aim of this study was to analyze the hydrological characteristics and water quality of the RWs located in urbanized areas with agricultural activity (in Carnaval and Del Gato streams) and in rural areas with extensive cattle farming (in Cajaravillas and Chubichamini streams), in order to recognize how different land uses modify the conservation conditions of the wetlands. The geohydrological analyses were carried out on a regional (basin), semi-detailed (sub-basin) and detailed (RWs) scale. The results showed that the overexploitation of groundwater affects the permanence of water in the wetlands, due to the disconnection between the phreatic level and the basal level of the RW located in the urbanized area with agricultural activity. In these latter, the supply of nutrients also influences the deterioration of water quality. The conclusion is that an environmental diagnosis of these RWs requires a regional approach to hydrological processes in order to adopt adequate actions for their conservation., Instituto de Limnología "Dr. Raúl A. Ringuelet"

Microplastics (MPs) are considered emerging pollutants and often enter aquatic ecosystems carried by currents and tides until they accumulate on the shorelines. In many cases they may be colonized by diverse microorganisms forming a community called plastisphere, which can even act as a reservoir for pathogenic microorganisms. This study carried out in the Río de la Plata estuary (southern coastal fringe, Argentina) focused on two main objectives, the analysis of the biofilm colonizing MPs under laboratory conditions, and the detection of bacteria indicating faecal contamination (Escherichia coli and Enterococci), in MPs from the intertidal sediment at coastal sites with different land uses, in the freshwater sector of the Río de la Plata estuary. The colonization experiment was carried out in the laboratory with water from the estuary for a period of 35 days (residence time of the water in the freshwater sector of the estuary). The results revealed a remarkable development and diversity of biofilm organisms from the second week of colonization on, covering the surface of the microplastic and thus masking this pollutant. On the other hand, the presence of faecal indicator bacteria in the MPs of the intertidal sediment was confirmed in all the studied sites, being proportionally higher on MPs found in areas influenced by sewage discharges. Los microplásticos (MPs) son considerados contaminantes emergentes y suelen ingresar en los ecosistemas acuáticos donde son transportados por las corrientes y mareas hasta acumularse en las costas. En muchos casos éstos pueden ser colonizados por diversos microorganismos conformando una comunidad denominada plastisfera y hasta pueden actuar como reservorio de microorganismos patógenos. En el estuario del Río de la Plata (Franja Costera Sur, Argentina), se realizó un estudio cuyo objetivo fue analizar el biofilm que se desarrolla sobre MPs en condiciones de laboratorio y analizar la presencia de bacterias indicadoras de contaminación fecal (Escherichia coli y Enterococos) en MPs hallados en el sedimento intermareal en sitios costeros con diferentes usos del suelo, en el sector de agua dulce del estuario del Río de la Plata. La experiencia de colonización se realizó en laboratorio con agua procedente del estuario durante un período de 35 días (tiempo de residencia del agua en el sector de agua dulce del estuario). Los resultados revelaron un notable desarrollo y diversidad de organismos del biofilm a partir de la segunda semana de colonización, recubriendo la superficie del microplástico y enmascarando así a este contaminante. Por otra parte, se confirmó la presencia de bacterias indicadoras fecales en los MPs del sedimento intermareal en todos los sitios estudiados, siendo proporcionalmente mayor en los MPs hallados en áreas influenciadas por descargas cloacales. Fil: Pazos, Rocío Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentina Fil: Suarez, Jimena Camila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentina Fil: Gomez, Nora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentina

Los bañados de desborde fluvial (BDF) desempeñan un papel importante en la ecología de las cuencas fluviales y en su capacidad de autodepuración. La demanda antrópica de espacio y agua pone en riesgo su biota y los beneficios ecosistémicos que brindan. Los objetivos del trabajo fueron analizar los ensambles de microorganismos que habitan en BDF de los partidos de La Plata y de Magdalena (Buenos Aires), relacionar sus variaciones con el impacto antrópico y evaluar cómo la microbiota puede ser indicadora de estos cambios ambientales. Se estudiaron los ensambles de diatomeas bentónicas, fitoplancton, zooplancton, ostrácodos y hongos de cuatro BDF: dos de ubicación periurbana con uso del suelo agrícola y hortícola (Del Gato y Carnaval) y dos de ubicación rural y uso ganadero (Cajaravillas y Chubichaminí). Las diferencias vinculadas con el uso del suelo se expresaron en la mayoría de los grupos, y los BDF se agruparon en rurales (con más especies sensibles a la contaminación y a la eutrofización) y periurbanos (donde fueron más importantes las especies muy tolerantes). En estos últimos, tanto los grandes grupos taxonómicos como los niveles tróficos estuvieron más relacionados con la vía detritívora que con la fotosintética, y en esos ambientes también fueron más relevantes las estrategias de los organismos para afrontar el estrés hídrico. Los resultados evidencian los efectos de la presión humana, la importancia que adquieren los microorganismos para evaluarla y la necesidad de una planificación adecuada del uso del territorio para evitar la pérdida de funciones y beneficios en estos ambientes., Riverine wetlands (RW) play a key role in the ecology of river basins and their selfpurification capacity. The anthropic demand for space and water puts their biota and the ecosystem benefits they provide at risk. The objectives of this work were to analyze the assemblages of microorganisms that inhabit the RW of La Plata and Magdalena (Buenos Aires), relate their variations to anthropogenic impact and evaluate how the microbiota can be an indicator of these environmental changes. Benthic diatoms, phytoplankton, zooplankton, ostracods, and fungi assemblages of four RW were studied: two of peri-urban location with agricultural and horticultural land use (Del Gato and Carnaval), and two of rural location and livestock land use (Cajaravillas and Chubichaminí). Differences linked to land uses were clearly expressed in most groups, with RWs grouped into rural (with more species sensitive to pollution and eutrophication) and peri-urban (with more species highly tolerant). In the latter, both the main taxonomic groups and the trophic levels were more restricted and more closely related to the detritivorous pathway than to the photosynthetic one, and the strategies to face water stress were emphasized. The results show the effects of human pressure, the importance that microorganisms acquire in its evaluation and the need of an adequate use of the territory to avoid the loss of functions and benefits of these environments., Instituto de Limnología "Dr. Raúl A. Ringuelet"

The goal of this study was to analyse the presence, abundance, types, size and colours of microplastics (MPs) in the soft tissue of the golden mussel Limnoperna fortunei in the freshwater-mixohaline tidal zone of Río de la Plata estuary. 240 mussels were analysed and the MPs were observed in the 96% of samples, being more abundant in the mussels that settled down close to the main sewage discharges, and in the maximum turbidity front. The average number of MPs/g and MPs/ind was 2.08 and 0.43, respectively. The 90% of MPs, were fibres and the most frequent sizes were >500 ≤1000 µm. The high density of L. fortunei on the coast of the Río de la Plata, its potential predators, and the presence of MPs in the soft tissue, warn the important role this mussel plays in the transfer of this pollutant through the trophic web of the estuary. Fil: Pazos, Rocío Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentina Fil: Spaccesi, Fernando Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentina Fil: Gomez, Nora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentina

RESUMEN El ejercicio físico puede ser una herramienta importante para el manejo de personas con enfermedades psiquiátricas, puesto que un notable número de estudios longitudinales y transversales ha demostrado que el mismo se constituye en una estrategia preventiva y en un enfoque adyuvante del tratamiento de los trastornos mentales. En ese sentido, se ha evidenciado que las formas más efectivas de ejercicio físico son los ejercicios aeróbicos (tales como caminar, trotar, andar en bicicleta, nadar, entre otros) y los de fortalecimiento. El objetivo de este artículo es presentar una actualización general acerca del ejercicio físico como tratamiento adyuvante de los trastornos mentales. Esta es una revisión narrativa, no sistemática, centrada en literatura primaria seleccionada de una búsqueda en PubMed, SciELO y LILACS. Los términos clave que se utilizaron fueron los siguientes: “ejercicio físico y salud mental”, “fisioterapia y salud mental”, “ejercicio físico y trastornos mentales” y “ejercicio físico y psiquiatría”. Se complementaron estos artículos con libros y capítulos de libros, resaltando hallazgos duplicados. Todos los miembros del equipo de investigación participaron en la revisión de la literatura. Aunque existen excelentes estudios y revisiones que analizan detalladamente el papel del ejercicio físico en el tratamiento específico de algunos trastornos mentales, se consideró que se necesitaba una revisión más general para brindar orientación a médicos psiquiatras y a fisioterapeutas en este campo de integración de la salud física y mental. ABSTRACT Physical exercise can be an important part of the management of people with psychiatric illnesses, since a considerable number of longitudinal and cross-sectional studies has shown that it constitutes a preventive strategy and an adjuvant approach to the treatment of mental disorders. In that sense, it has been demonstrated that the most effective forms of physical exercise are aerobic exercises (such as walking, jogging, cycling, swimming, among others) and strengthening. The aim of this article is to present a general update about physical exercise as an adjuvant treatment of mental disorders. This is a narrative review, not systematic, focused on primary literature selected from a search in PubMed, SciELO and LILACS. The key terms used were: “physical exercise and mental health”, “physiotherapy and mental health”, “physical exercise and mental disorders” and “physical exercise and psychiatry.” These articles were supplemented with books and book chapters, highlighting duplicate findings. All members of the research team participated in the review of the literature. Although there are excellent studies and reviews that analyze in detail the role of physical exercise in the specific treatment of some mental disorders, it was considered that a more general revision was needed to provide guidance to psychiatrists and physiotherapists in this field of integration of physical and mental health.

Fil: Cochero, Joaquin. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - La Plata. Instituto de Limnologia "Dr. Raul A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnologia; Argentina

Fil: Paz, Laura Estefania. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - La Plata. Instituto de Limnologia "Dr. Raul A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnologia; Argentina

Sunlight is a crucial environmental factor for photosynthesis. Plant density affects both quality and quantity at light penetration into the canopy. The effects of plant density on the expression of photomorphogenic traits in cultivated spring rapeseed (Brassica napus L.), and their consequences on seed production per unit area are unknown. The aims of this work were to: i) analyze the magnitude of shade avoidance responses to plant densities in five spring rapeseed genotypes, ii) describe the dynamics of floral branching in response to genotype and plant density, and iii) study yield and its components and seed quality in field-cultivated plants with contrasting plant densities (15 and 240 pl m−2). Rosette diameter was the main attribute of vegetative plasticity modified by plant density, without significant changes in petiole length. Plant density changed the relationship between intercepted solar radiation (ISR) and red/far red ratio (R/FR) during crop development, but at flowering all densities reached ISR = 95% and R/FR ratio

The picoplankton is an important component of aquatic food webs and plays a significant biogeochemical and ecological role in the environment. Little is known about this fraction of the plankton in temperate estuaries and especially in South America. In this article, we study the absolute and relative importance of the picoplankton along an annual cycle, and their relationship with physical and chemical variables in the Rio de la Plata estuary. We also review the existing research in estuaries around the world concerning this community and present our results in a global context. The seasonal variation in the abundance of the different groups analyzed was very noticeable. Phycocyanin-rich picocyanobacteria (Pcy) were the main component (in abundance and in biovolume) of the picophytoplankton (PPP) almost during the whole year, with a maximum abundance of 7.3 × 105 cell mL−1 in summer, three orders of magnitude higher compared to autumn-winter. Picoeukaryotes, larger phytoplankton and heterotrophic bacteria showed the same seasonal trend, although with a lower range of variation than that of the Pcy. Considering all the phototrophic planktonic fractions, in terms of biomass, the PPP reached a maximum of 43% of the total biomass in spring. The dynamics of PPP found in this area are consistent with the observed in other temperate estuaries, where temperature is the main variable that influences its development, and with a high seasonal variation. Additionally, the absolute and relative importance of Pcy showed a consistently increasing trend towards lower latitude estuaries. The review also showed us that there is scarce information related to the picoplankton fraction in the Southern Hemisphere, its sanitary implications due to their potential of toxicity or their ecological role in coastal zones. The results presented here show the importance of this fraction, not only in Rio de la Plata, but in many estuaries of the world, with a clear increase of relative abundance as we approach the equator.

Diatoms respond to toxicants in lotic systems, and they are commonly considered to be sensitive indicators in environmental safety assessment. In addition to the structural characteristics of the algal populations, recent studies have shown that endpoints such as nuclear anomalies or diatom motility measures can be affected quickly by environmental changes. We sought to determine if cell density, cell size, nuclear anomalies and motility of the diatom Nitzschia palea were useful indicators of sediment quality from agricultural streams. For this purpose, we exposed cultures of the diatom to elutriates from sediments of a stream that flows through an intensive agricultural area, and measured the responses of the populations for 7 days in laboratory tests. The bioassays showed that motility measures in Nitzschia palea and the condition of their nuclear membranes rapidly reflected the effects of sediment quality after only 48 h of exposure; mean cell density and length were affected by day 7. The sediment elutriates affected cell movements by shortening the total path length and decreasing cell velocity; they also increased the number of cells with nuclear membrane breakage. Our results from these bioassays show that diatom motility measurements and the condition of the nuclei might be indicators that respond faster to impacts than the traditional structural parameters, such as cell density, specific composition of the assemblage or diversity metrics of the algal communities more often used in biomonitoring., Instituto de Limnología "Dr. Raúl A. Ringuelet"

Introducción: El tratamiento antimicrobiano para los pacientes neutropénicos febriles (NF) se ha convertido en un desafío debido a la emergencia de microorganismos multirresistentes (MOR). El objetivo de este trabajo es analizar las características de estos pacientes y la incidencia de MOR. Materiales y métodos: Estudio retrospectivo, observacional y descriptivo desde junio de 2015 hasta agosto de 2017 en adultos neutropénicos febriles hospitalizados en un hospital público de la ciudad de Buenos Aires. Se analizaron características demográficas, clínicas y microbiológicas, incluyendo los siguientes MOR: enterobacterias productoras de carbapenemasas (EPC) y beta-lactamasas de espectro extendido (BLEE), Acinetobacter baumannii complex, Enterococcus vancomicina resistente (EVR) y Stenotrophomonas maltophilia. Resultados: Fueron incluidos 32 pacientes, 56% mujeres con 84% de neoplasias hematológicas. Hubo colonización por EPC o EVR en el 59% de los pacientes. Se registraron 148 episodios infecciosos con 41% de documentación microbiológica. Los MOR fueron responsables del 25% de los episodios, siendo los más frecuentes Klebsiella pneumoniae productora de carbapenemasa y BLEE; los focos más frecuentes fueron bacteriemias e infecciones urinarias. Los pacientes con leucemias agudas (67%) presentaron colonización por EPC o EVR en el 80%. El tratamiento fue inadecuado en el 63% de las infecciones por MOR y en el 12% por microorganismos sensibles (MS) (p

The purpose of this study was to analyze the rate of sporulation, richness, and spore diversity of dematiaceous and Ingoldian fungi colonizing Typha latifolia leaves during a 40-day period of decomposition, as well as the loss of mass in Typha latifolia, in four riverine wetlands of Pampean plain (Argentina) with different water quality. Higher sporulation rates, richness, and diversity of the fungi as well as loss of mass of the leaves that they colonized were associated with lower water quality. Anguilospora longissima, Arthrinium sp., Margaritispora aquatica, and Tricellula botryosa were dominant taxa. Redundancy analysis showed two fungal assemblages related to different environmental conditions. One assemblage was related to higher nutrient levels and higher temperature, characterized mainly by dematiaceous fungi. The other assemblage was related to higher levels of pH and dissolved oxygen, which was mainly represented by Ingoldian fungi. The results obtained in our study demonstrated the link between these fungal assemblages and changes in water quality, revealing their potential as indicators of environmental changes in rivers exposed to different types of land use., Instituto de Limnología "Dr. Raúl A. Ringuelet"

Risk factors for venous thromboembolism in cancer vary between tumours. Leucocytosis, thrombocytosis, tumour histology and vascular compression may drive thrombosis in ovarian cancer. Thrombosis developed in 13.4% of our patients. Higher median leucocyte, neutrophil and monocyte counts were related to thrombosis. Thrombocytosis >350 × 109 /L was frequent (63.8%), but not predictive of thrombosis. Identification of prothrombotic biomarkers may help personalise preventive treatments.

Determining the optimum time for rapeseed harvest is challenging due to non-uniform seed maturity resulting from asynchronous flowering and pod dehiscence from sequential racemes. Identifying physiological maturity (PM) by visual methods is subjective and results can be affected by environmental conditions. PM can be determined using a quantitative model based on seed water concentration (SWC) as previously demonstrated for several other crops, although not yet developed for rapeseed crop. The objective of this work was to study the relationship between the dynamics of seed dry weight and water concentration in seven spring rapeseed cultivars grown at two contrasting densities (15 and 60 pl m−2) in three experiments at one location in Buenos Aires (Argentina). We evaluated the timing of PM on the basis of SWC in seeds located in the main raceme, second and fourth floral branches. The evolution of seed fresh and dry weight was followed bi-weekly from the beginning of flowering to harvest maturity. In Exp. 1, the grain-filling duration ranged from 39 to 57 days (700–1100 °C d) and the growth of seeds from floral branches finished 3–8 days later than those from the main raceme. Seed dry weight at PM ranged from 2.4 to 2.7 and from 3.0 to 3.2 mg for Lynx and Monty cultivars, respectively, without significant effects of floral position or plant density. Bi-linear functions were used to fit the relationship between relative seed dry weight (RSDW) and SWC relationships (R2 from 0.85 to 0.95). Across cultivars and floral positions, PM was attained when seeds exhibited 46.3 ± 0.7% SWC (R2 = 0.90, P < 0.001, n = 441). This model was validated against independent data from Exps. 2 and 3, successfully simulating the dynamics of relative seed dry weight based on fruit WC (r = 0.88; P < 0.001, n = 275). At PM, the water content (WC) of whole pod was about 70% and the pod shattering began after this point, when the WC of the pod dropped drastically. We conclude that under non-stressful conditions, PM in rapeseed occurs at 46% SWC. Swathing can be conducted from SWC < 46%, instead of the currently recommended 35%, advancing the harvest and leaving the land available for sowing the next crop, which would represent an advantage for double cropping in intensified agricultural systems. Fil: Menendez, Yesica Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina Fil: Botto, Javier Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina Fil: Gomez, Nora V.. Universidad de Buenos Aires. Facultad de Agronomía; Argentina Fil: Miralles, Daniel Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina Fil: Rondanini, Deborah Paola. Universidad Nacional de Lomas de Zamora. Facultad de Ciencias Agrarias. Instituto de Investigación en Producción Agropecuaria Ambiente y Salud. - Comisión de Investigaciones Científicas de la Provincia de Buenos Aires. Instituto de Investigación en Producción Agropecuaria Ambiente y Salud; Argentina

The objective was to establish possible temporal patterns in the microplastics (MPs) abundance in the water and in the intertidal sediment in an urbanized location of the Rio de la Plata estuary (Argentina), in relation to environmental factors. The site was sampled monthly for a year (February 2019–January 2020). The presence of MPs was recorded, being more abundant in February in the water (110 MPs m−3) and in April in the sediment (613 MPs m−2). The types of MPs found were fibers, fragments, pellets, film and foam; while the polymers identified were polyethylene (PE) and polypropylene (PP). Regarding the environmental variables, the predominance of wind from the NE direction was related to a greater accumulation of MPs in the sediment, while wind from the NO direction was associated with a lower abundance of MPs in the water. Also, MPs abundance was negatively related to the larger sizes of sediment particles.

The colonisation patterns of diatom assemblages were studied on artificial substrates in lowland streams with different urban pollution levels. Density, diversity, colonisation rates, ecological guilds and cell size classes of the assemblage at each of two sites were followed for 1 week. In addition, assemblages growing on glass, in natural epipelic biofilm and in water were compared at each site. At both sites, diatom colonisation on glass substrates had already started after 30-min exposure. At the less polluted site, total diatom density was higher, along with the proportion of low-profile and motile species, and there was a higher amount of diatoms in size class 5 (>1500μm3). At the more polluted site, species from the high-profile guild and size class 3 (300–599μm3) dominated. Ecological traits (ecological guilds and size class) were not sensitive enough descriptors of early colonisation in nutrient-rich lowland, but the largest cells constituted the first settlers. The results show that the assemblage developed on artificial substrata was a good proxy of the composition in the sediment.

Agricultural activities can affect the delivery of nutrients to streams, riparian canopy cover, and the capacity of aquatic systems to process nutrients and sediments. There are few measures of nutrient uptake and metabolism from tropical or subtropical streams in general, and even fewer from tropical regions of South America. We examined ammonium (NH₄ ⁺) and soluble reactive phosphorus (SRP) retention in streams in Brazil and Argentina. We selected 12 streams with relatively little or extensive agricultural activity and conducted whole-stream nutrient additions and measurements of gross primary production and ecosystem respiration. We used multiple linear regression to determine potential drivers of nutrient uptake metrics across the streams. Nutrient concentrations and retention differed significantly between land use categories. Both NH₄ ⁺ and SRP concentrations were higher in the agricultural sites (means of 161 and 495 μg l⁻¹, respectively), whereas metabolic rates were slower and transient storage was smaller. Our analysis indicated that agriculture increased ambient uptake lengths and decreased uptake velocities. The regression models revealed that ambient SRP had a positive effect on NH₄ ⁺ uptake and vice versa, suggesting strong stoichiometric controls. Drivers for nutrient uptake in streams with low-intensity agriculture also included canopy cover, temperature, and ecosystem respiration rates. Nutrient assimilation in agricultural sites was influenced by a higher number of variables (gross primary production for SRP, discharge, and transient storage for both nutrients). Our results indicate agricultural activity changes both the magnitude of in-stream nutrient uptake and the mechanisms that control its variation, with important implications for South American streams under agricultural intensification., Instituto de Limnología "Dr. Raúl A. Ringuelet"

In this study we explored the use of less conventional diatom metrics (motility, nuclear abnormalities and ecological guilds) to measure changes in diatom assemblages related to the transfer of epipelic communities from urban impacted streams to less impacted sites. Three lowland streams in the Argentine Pampean plain were selected, and two sites were established per stream for a total of six sites. Three sites were referenced as low urban impact (LI), as they run through peri-urban areas, and three downstream sites were referenced as high impact sites (HI), since they run through a dense urban area. Six germination trays filled with stream sediment were placed at each HI site, and three at each LI site, and left to be colonized for 30 days before transferring three trays from the HI sites to their respective LI site upstream. Samples were collected at days 0, 15, 30 and 45 days from each tray, and diatom species were identified and classified into ecological guilds. Motility variables were measure per individual of the genera Nitzschia (path length, velocity and maximum velocity) through video recording. Also, the frequency of abnormal nuclear locations and nuclear membrane breakage were determined. Results showed that there were no significant differences in any motility metrics, while the nuclei variables exhibited higher proportion of abnormally positioned nuclei and nuclear membrane breakage at the HI sites. The proportion of nuclear membrane breakage decreased over time in the translocated assemblage, indicating that it could be a sensitive indicator of water quality improvement, while the ecological guilds showed significant differences on the proportion of high profile and motile diatoms. The improvement in water quality produced a significative increase in the proportion of the high profile guild in the translocated biofilm. Despite the motile forms being the dominant group, the water quality improvement allowed the high profile forms, to colonize the substrate. These results emphasize the possible use of the ecological guilds as a suitable indicator of water quality improvement in Pampean streams, especially in nutrient rich environment. These tools can provide a rapid assessment of diatom condition and could be considered supplementary to biomonitoring protocols in lowland streams. Fil: Nicolosi Gelis, María Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentina Fil: Cochero, Joaquin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentina Fil: Donadelli, Jorge Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentina Fil: Gomez, Nora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentina

We assessed the effects of nutrient enrichment on three stream ecosystems running through distinct biomes (Mediterranean, Pampean and Andean). We increased the concentrations of N and P in the stream water 1.6–4-fold following a before–after control–impact paired series (BACIPS) design in each stream, and evaluated changes in the biomass of bacteria, primary producers, invertebrates and fish in the enriched (E) versus control (C) reaches after nutrient addition through a predictive-BACIPS approach. The treatment produced variable biomass responses (2–77% of explained variance) among biological communities and streams. The greatest biomass response was observed for algae in the Andean stream (77% of the variance), although fish also showed important biomass responses (about 9–48%). The strongest biomass response to enrichment (77% in all biological compartments) was found in the Andean stream. The magnitude and seasonality of biomass responses to enrichment were highly site specific, often depending on the basal nutrient concentration and on windows of ecological opportunity (periods when environmental constraints other than nutrients do not limit biomass growth). The Pampean stream, with high basal nutrient concentrations, showed a weak response to enrichment (except for invertebrates), whereas the greater responses of Andean stream communities were presumably favored by wider windows of ecological opportunity in comparison to those from the Mediterranean stream. Despite variation among sites, enrichment globally stimulated the algal-based food webs (algae and invertebrate grazers) but not the detritus-based food webs (bacteria and invertebrate shredders). This study shows that nutrient enrichment tends to globally enhance the biomass of stream biological assemblages, but that its magnitude and extent within the food web are complex and are strongly determined by environmental factors and ecosystem structure

We examined the responses of the phytoplankton and the bacterioplankton of the freshwater zone of the Rio de la Plata estuary when exposed to an addition of hexavalent chromium (Cr⁺⁶). The planktonic community from a coastal site was exposed to a chromium increase of 80 μg L⁻¹ for 72 h in laboratory conditions. The results showed a decrease in the concentration of Cr⁺⁶ by 33% in the treatments, along with significant decreases in chlorophyll-a (63%), the chlorophyll-a:pheophytin-a ratio (33%), oxygen production (37%), and in the total density of the phytoplankton (15%). The relative abundance of chlorophytes and diatoms decreased, while the cyanobacteria thrived. Finally, the total bacterial density and the density of viable bacteria decreased. These results show that even small increments in Cr⁺⁶ can cause significant effects on the phytoplankton and bacterioplankton, which could potentially affect other trophic levels of the community, risking alterations of the entire ecosystem., Facultad de Ciencias Naturales y Museo, Instituto de Limnología "Dr. Raúl A. Ringuelet"

This study explores in plankton samples the abundance, distribution, size, types (fibres and fragments), colours of the microplastics (MPs) and its relation with the characteristics of the plankton (size and morphology) of the Río de la Plata estuary. Water samples were collected in triplicate in freshwater-mixohaline tidal zone of the estuary, in ten sampling sites located along 150 km of coast, in two periods (September–November 2016 and April–June 2017). The results revealed the presence of MPs in all the samples analysed, with a dominance of fibres and sizes >500 ≤ 1000 μm, and blue colour being more frequent. The MPs distribution was significantly different among sampling sites, being more abundant in the most urbanized sites, sewage discharges and near the maximum turbidity front. The mean density, in the two samplings analysed, were 164 and 114 MPs m−3. The fibres amount was significantly different among sites. The MPs integrated a planktonic community dominated by pico-microphytoplankton, mainly conformed by filaments/chains and solitary forms and by micro-mesozooplankton. The comparative analysis of plankton and MPs demonstrated that a fraction of the latter showed a frequency range of size that coincides with the most common sizes of plankton (≤500 μm). The mean percentage of MPs items in relation to zooplankton was 0.36% (sampling 1) and 1.20% (sampling 2) and for phytoplankton was 0.0002% (sampling 1) and 0.0005% (sampling 2). The correlations between the MPs concentration and habitat quality (IHRPlata index) were statistically significant, on the contrary correlations between the MPs concentration and measured environmental variables were not found. The findings of this study emphasises the need for a better treatment of urban waste, which would contribute to reducing the entry of this pollutant into the ecosystem. The presence of microplastics in plankton samples on the coast of the Río de la Plata estuary. Fil: Pazos, Rocío Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentina Fil: Bauer, Delia Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina Fil: Gomez, Nora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentina

We analyzed the diatom assemblages inhabiting the epipelic biofilm of a Pampean stream, characterized by their high basal nutrient levels, when exposed to a continuous surplus of inorganic nutrients. An in situ experience was conducted, increasing concentrations of N and P in water 3-fold from the basal concentration. Nutrient enrichment was achieved by the use of fertilizer bags distributed along the reach. The period of exposure was of 14 months. The effects of nutrient enrichment were analyzed following a BACIPS ANOVA design. The changes in nutrient concentration were associated with a significant increase in diatom density and a decrease in species richness and diversity. The additional nutrient load also caused the change in the diatom taxa proportion, favoring motile forms, Nitzschia species mainly. The fertilization in La Choza, caused a mild to moderate effect, indeed not immediate, on the diatom assemblage. These delayed responses of moderate intensity could be related with intrinsic characteristics of diatom assemblages pre-adapted to nutrient-rich environments. The rising urbanization and agricultural activity in the Pampean plain, may seriously impair the biodiversity of its rivers if the entrance of nutrients to these ecosystems is not mitigated., Instituto de Limnología "Dr. Raúl A. Ringuelet"

The presence of microplastics (MPs) in gut contents of coastal freshwater fish of the Rio de la Plata estuary was studied. Samples were taken in six sites where 87 fish belonging to 11 species and four feeding habits were captured. Presence of MPs was verified in the 100% of fish. The fibres represented the 96% of MPs found. The number of MPs in gut contents was significantly higher close to sewage discharge. There was not found relationship between number of MPs and fish length, weight or feeding habit. The spatial differences in mean number of MPs in fish observed in this study, suggest that environmental availability of MPs could be of great importance to explain the differences found among sampling sites analysed. This work represents the first study about the interaction between MPs and aquatic organisms in this important estuarine ecosystem of South America., Instituto de Limnología "Dr. Raúl A. Ringuelet"

La situación ideal es volver a reimplantar un diente exarticulado inmediatamente después de la avulsión porque el tiempo extra oral es un factor determinante para el éxito del tratamiento y para un buen pronóstico. Sin embargo, no siempre es posible. El éxito de la reimplantación depende de una serie de factores, los cuales pueden contribuir a acelerar o minimizar la aparición de la reabsorción radicular o anquilosis, teniendo un rol importante en este proceso el tipo y características del me dio utilizado para el almacenamiento temporal durante el tiempo transcurrido entre la avulsión y la reimplantación. Mantener el diente en un medio húmedo adecuado, puede preservar la vitalidad de las células del ligamento periodontal que permanecen en la superficie de la raíz siendo esta la clave del éxito de la reimplantación. Investigaciones recientes impulsaron el desarrollo de medios de almacenamiento que reproducen condiciones similares el medio ambiente alveolar, con osmolalidad adecuada(presión celular), pH, metabolitos nutricionales y glucosa, creando las mejores condiciones posibles para el almacenamiento. El presente artículo revisa la literatura referida a los diferentes medios de almacenamiento que han sido investigados para dientes avulsionados basado en documentos recuperados de PubMed/Medline, Lilacs. Varios estudios coinciden que la leche entera pasteurizada es uno de los medios con mejor pronóstico entre otras soluciones que puedan estar disponibles en la escena de un accidente.