Factors driving seed dispersal in a neotropical river-floodplain system

La dispersión es un proceso clave que afecta la diversidad de las comunidades naturales. Abordamos la hidrocoria de semillas de plantas de humedales en la llanura aluvial del río Paraná Medio. Primero estudiamos la dispersión de semillas a la deriva de macrófitas en el canal principal del río Paraná (MC), en un canal secundario de alta descarga (HD) y en dos canales de baja descarga (LD) durante una inundación extraordinaria. Luego analizamos experimentalmente el efecto del agua estancada (SW) y el agua en movimiento (MW) sobre la flotabilidad de semillas de diferentes comunidades de plantas. Registramos semillas de 27 taxones distribuidos en 12 familias. La riqueza de taxa varió de 17 en LD a 25 en MC e incluyó semillas de plantas terrestres, palustrinas y acuáticas. La descarga del río no afectó la riqueza y densidad de semillas, lo que probablemente se asoció con un proceso de homogeneización causado por la inundación. La flotabilidad de las semillas difirió significativamente entre los tratamientos de movimiento de agua independientemente de la comunidad fuente, durando más en SW que en MW. Nuestros resultados sugieren que los macrófitos a la deriva contribuyen a la dispersión de semillas de varias comunidades en el río Paraná Medio, y probablemente a largas distancias. Además, la flotabilidad de las semillas podría ser más importante para la dispersión superficial en sistemas de baja energía, donde la dispersión subacuática puede ser difícil debido a la falta de corriente.Dispersal is a key process affecting the diversity of natural communities. We addressed hydrochory of wetland plantseeds in the Middle Paraná River floodplain. We first studied seed dispersal by drifting macrophytes in the ParanáRiver main channel (MC), in a high discharge secondary channel (HD) and in two low discharge channels (LD) duringan extraordinary flood. We then experimentally analyzed the effect of standing (SW) and moving water (MW) onseed buoyancy of different plant communities. We recorded seeds of 27 taxa distributed in 12 families. Taxa richnessranged from 17 in LD to 25 in MC, and included seeds of terrestrial, palustrine and aquatic plants. River dischargedid not affect seed richness and density, which was probably associated with a homogenization process caused bythe flood. Seed buoyancy significantly differed between water movement treatments independently of the sourcecommunity, lasting longer in SW than in MW. Our results suggest that drifting macrophytes contribute to seeddispersal of several communities in the Middle Paraná River, and probably over long distances. Furthermore, seedbuoyancy might be more important for surficial dispersal in low-energy systems, where subaqueous dispersal maybe difficult due to the lack of current.Fil: Facelli Fernández, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Schneider, Berenice. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Zilli, Florencia Lucila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin

Multiscale environmental heterogeneity in a large river-floodplain system

River-floodplain systems host very high biodiversity and provide a great variety of ecosystem services due largely to their high environmental heterogeneity, which is strongly dependent on spatial and temporal scales of observation. We aimed to describe the main patterns of environmental variation of the subtropical system of the Middle Paraná River at different scales of analysis using univariate and multivariate statistics. Physical, chemical and biological variables were analyzed during different hydro-sedimentological phases along four consecutive years in 31 aquatic environments. We considered four aquatic habitat types with different degrees of hydrological connectivity and water flow characteristics (major rivers, secondary channels, floodplain lakes permanently connected to the major rivers, and floodplain lakes temporarily connected to the major rivers) from two geomorphologic units with different drainage patterns: anastomosing and meandering. The environmental heterogeneity was mainly associated with the habitat types and relative contributions of lateral tributaries with different water qualities to each unit, in combination with the influence of the hydro-sedimentological regime. The heterogeneity of the system was significantly higher during low water than during high water phases. However, although the extreme flood reduced dissimilarities between habitat types within each geomorphologic unit, it increased differences between major rivers and between units. In conclusion, at different spatial scales, floods may simultaneously have a homogenization effect due to increased hydrological connectivity and a differentiation effect due to enhanced inputs of water from regions with variable geological characteristics and land uses. Finally, geomorphologic units can play a key role in maintaining the environmental heterogeneity during floods of high magnitude, even when land barriers among aquatic environments disappear.Fil: Mayora, Gisela Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Scarabotti, Pablo Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Schneider, Berenice. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Alvarenga Mariani, Patricio Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Marchese Garello, Mercedes Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin

Outcomes of the first 54 pediatric patients on long-term home parenteral nutrition from a single Brazilian center

Objectives: Data on multidisciplinary programs dedicated to home parenteral nutrition (HPN) in Latin America are limited. This study describes the results of the first multidisciplinary pediatric intestinal rehabilitation program for HPN at a public tertiary hospital in Brazil. Methods: We retrospectively reviewed patients aged 0–18 years with intestinal failure (IF) who required parenteral nutrition (PN) for >60 days between January/2014 and December/2020. Results: Fifty-four patients were discharged on HPN (15 achieved enteral autonomy, 34 continued on HPN at the end of the study, 1 underwent intestinal transplantation, and 4 died). The median (IQR) age at the study endpoint of patients who achieved enteral autonomy was 14.1 (9.7–19) versus 34.7 (20.4–53.9) months in those who did not achieve enteral autonomy. Overall prevalence of catheter-related thrombosis was 66.7% and catheterrelated bloodstream infection rate was 0.39/1000 catheter-days. Intestinal failure-associated liver disease (IFALD) was present in 24% of all patients; none of the patients who achieved enteral autonomy had IFALD. All patients showed significant improvement in anthropometric parameters during the HPN period. The sociodemographic characteristics of the patients’ family members were mothers less than 20 years old (7.5%), schooling time more than 10 years (55.5%), and household income between 1 and 3 times the minimum wage (64.8%). The 5-year survival rate for HPN is 90%, and 27.7% of patients achieve enteral autonomy. Conclusion: The treatment of pediatric patients with IF followed by a multidisciplinary pediatric intestinal rehabilitation program with HPN is feasible and safe in the Brazilian public health system

La interdisciplina en el estudio de la forma urbana

Con esta edición se busca crear una plataforma analítica y de discusión sobre la importancia de la interdisciplina en el estudio de la forma de la ciudad. Por ello, en esta publicación se aborda el tema “Forma urbana e interdisciplina” a partir de cuatro ejes temáticos: Análisis y diagnósticos de la forma urbana; procesos históricos de la forma urbana; planes y proyectos urbanos e impactos en la forma urbana. Se espera que el material presentado cumpla con sus objetivos y que su lectura contribuya a ampliar el panorama de reflexión y discusión sobre el tema de la interdisciplina en el estudio de la forma urbana.Elizabeth Espinosa Dorantes; Christof Göbel; Salomón González Arrellano (sic), coordinadore

The complete genome sequence of Chromobacterium violaceum reveals remarkable and exploitable bacterial adaptability

Chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of tropical biodiversity around the world. Its complete genome sequence reveals (i) extensive alternative pathways for energy generation, (ii) ≈500 ORFs for transport-related proteins, (iii) complex and extensive systems for stress adaptation and motility, and (iv) wide-spread utilization of quorum sensing for control of inducible systems, all of which underpin the versatility and adaptability of the organism. The genome also contains extensive but incomplete arrays of ORFs coding for proteins associated with mammalian pathogenicity, possibly involved in the occasional but often fatal cases of human C. violaceum infection. There is, in addition, a series of previously unknown but important enzymes and secondary metabolites including paraquat-inducible proteins, drug and heavy-metal-resistance proteins, multiple chitinases, and proteins for the detoxification of xenobiotics that may have biotechnological applications

Primer registro de Najas marina (Hydrocharitaceae) y listado florístico de hidrófitas sumergidas en el Bajo Paraná (Argentina)

Se comunica el registro de Najas marina L., una hidrófita completamente sumergida,en el Bajo Paraná (Argentina) como nueva cita para su flora y se revisan brevemente aspectos de su ecología (rasgos biológicos, hábitat y distribución). Además, se presenta un listado de las 24 especies de hidrófitas sumergidas (en 12 familias y 15 géneros)que han sido registradas para la extensa planicie de inundación del Bajo Paraná.Najas marina L., a completely submersed hydrophyte, is communicated as a new record for the flora of the Lower Paraná River floodplain (Argentina), and aspects relative to its ecology (biological traits, habitat and distribution) are briefly reviewed. Additionally, a check list of the 24 submersed hydrophyte species (12 families, 15 genera) recorded in the large Lower Paraná floodplain is provided.Fil: Brumnich, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Schneider, Berenice. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin

Phenolic exudates from Ludwigia peploides and Azolla sp. enhance germination of Polygonum ferrugineum seeds

The release of allelochemicals by aquatic macrophytes can inhibit or benefit other plants. Here we studied allelopathic interactions between syntopic species native to the Neotropical region. First, we quantified the phenolic exudation in monospecies cultures of Ludwigia peploides (L) and Azolla sp. (A) and in co-cultures of both species growing together (A+L) compared to control water. Then, we studied the germination of Polygonum ferrugineum seeds exposed to the exudates and control water. Incubation water from L had a significant lower pH than the other treatments, and a lower conductivity than the control. L alone or in co-culture with A reduced the dissolved oxygen content of the incubation water. Phenolic compounds were undetectable in control water (C) and the A treatment. In water of L and A+L treatments, phenolic concentration increased during the 5-day bioassay, with significant differences from day 3 on compared to treatments C and A. On day 5, more phenolic exudates were found in the A+L than in the L treatment. The germination rate but not germination speed was significantly higher in P. ferrugineum seeds treated with A+L exudates, and correlated positively with the phenolic concentration. Our results suggest that the allelopathic potential of aquatic macrophytes such as L. peploides can be higher in multispecies patches than in monospecies ones. Furthermore, phenolic exudates of macrophytes might stimulate the germination of plants native to the same region, which may have implications in the formation of vegetation patterns in aquatic ecosystems.Fil: Schneider, Berenice. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Mayora, Gisela Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin

Narrativas transmidiáticas: análise da campanha publicitária da marca Arezzo

This article analyzes Arezzo’s Winter 2016 advertising campaign, using the principles of Jenkins (2009) for Transmedia Storytelling. To accomplish the goals of this work it was decided to use the bibliographical research, qualitative research, and case study. In the analyzed campaign a new type of storytelling was created: the interactive authoring in the network. The construction of this complex narrative allows the format to be able to expand and distribute its content through several communication platforms, connecting different audiences who personalize their experience with the product presented.Este artigo analisa a campanha publicitária de Inverno 2016 da marca Arezzo, utilizando os princípios de Jenkins (2009) para narrativas transmidiáticas. Para cumprir os objetivos deste trabalho, optou-se por utilizar a pesquisa bibliográfica, a pesquisa qualitativa e o estudo de caso. Na campanha analisada foi criado um tipo de storytelling: a autoria interativa na rede. A construção desta narrativa complexa permite que o formato consiga ampliar e distribuir o conteúdo por meio de diversas plataformas comunicacionais conectando, assim, diferentes públicos que personalizam sua experiência com o produto apresentado

Turbidity and dissolved organic matter as significant predictors of spatio-temporal dynamics of phosphorus in a large river-floodplain system

Phosphorus (P) inputs are increasing in river‐floodplain systems, but the factors whichinfluence the dynamics of this nutrient are not clear. To assess P dynamics in this kindof river, the main channel of the Middle Paraná River, 3 anabranches, 9 secondarychannels, and 20 lakes (7 permanently connected and 13 temporarily connected tothe fluvial system) were sampled. Multiple linear regressions were applied to explainspatio‐temporal patterns of P through commonly measured limnological variables.Particulate P increased during the sediment peak (evaluated through turbidity). Solublereactive P (SRP) was positively associated with dissolved organic matter (DOM,mainly the chromophoric fraction), which increased during high waters in the fluvialsystem but was highly variable in each kind of aquatic environment. In temporarilyconnected lakes, vegetated zones dominated by emergent macrophytes displayedthe highest SRP and chromophoric DOM concentrations. The flood and sedimentpeak positively affected P load in the river due to the increase in dissolved and particulatefractions, respectively. In addition, particle‐bound alkaline phosphatase activitywas positively associated with SRP concentration and load. These results suggest thatthe sediment peak incorporates particulate P in the system while the floodplain is a Psource during floods through exportation of the dissolved fraction. Dissolved P couldbe largely exported associated with DOM, which stimulates phosphatase biosynthesisby decreasing P bioavailability. The effect of aquatic macrophytes on P dynamicsseems to be influenced by DOM exudation. According to these considerations,DOM should be taken into account to analyse P dynamics in river‐floodplain systems.Fil: Mayora, Gisela Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Schneider, Berenice. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Rossi, Andrea Silvana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin