Fluctuating salinity improves survival of the invasive freshwater golden mussel at high salinity: implications for the introduction of aquatic species through estuarine ports

In order to evaluate the resilience to salinity as a factor enhancing freshwater invasiveness, we assessed the tolerance of the mussel Limnoperna fortunei to salinity conditions mimicking changes in an estuary. We tested mussel mortality in 30-day exposures to constant and fluctuating salinities at different temperatures in the laboratory. Test conditions simulated different seasons of the year and locations with increasing influence of marine waters in Río de la Plata, Argentina. Significant mortality (31% after 30 d) was observed at a constant salinity of 2?, increasing to 45% and 57% at 5? and 10?, respectively. In contrast, considerably greater tolerances were observed when conditions in the experimental chamber fluctuated between salt- and fresh water. No significant mortality was observed in mussels exposed to a salinity cycle with abrupt salinity changes ranging 1-23? (mean 2.68?) over a month. Tolerance to this type of regime was unaffected by different temperatures within ambient ranges. Tests at constant salinity underestimate the tolerance of this and probably other freshwater nonindigenous species (NIS) to short term saltwater exposures. Estuarine ports account for ca ⅔ of non-marine ports globally, thus constituting hotspots for NIS propagule pickup and delivery into continental aquatic ecosystems via shipping vectors. The tolerance of L. fortunei to estuarine conditions likely contributes to the species? remarkable invasive success. These results highlight the need to determine causes of invasiveness, and study NIS traits not alone but in combination with transport network properties.Fil: Sylvester, Francisco. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Ecologia, Genetica y Evolución; Argentina;Fil: Notaro, Carolina. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Ecologia, Genetica y Evolución; Argentina;Fil: Cataldo, Daniel. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Ecologia, Genetica y Evolución; Argentina; Consejo Nacional de Invest.cientif.y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Museo Arg.de Cs.nat;Fil: Boltovskoy, Demetrio. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Ecologia, Genetica y Evolución; Argentina; Consejo Nacional de Invest.cientif.y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Museo Arg.de Cs.nat

Dinámica poblacional y potencial bioindicador de contaminación acuática del molusco bivalvo Corbicula fluminea en el delta del Río Paraná

La estructura y la dinámica poblacional del molusco invasor Corbicula fluminea, así como su potencial como especie bioindicadora de estrés ambiental,fueron analizados en el delta inferior del río Paraná entre abril de 1995 y octubre de 1996. Muestras de agua y sedimentos fueron colectadas en cuatro sitios con diferentes niveles de contaminación para evaluar el impacto antropogénico por medio de análisis químicos y bioensayos de laboratorio. Se determinaron las concentraciones de bifenilos policlorados (BPCs), plaguicidas organoclorados (POCs), hidrocarburos alifáticos (HALs), hidrocarburos aromáticos (HARs) y metales pesados (MP) en el agua superficial, el agua de profundidad y los sedimentos. Estas mismas tres fases también se sometieron a ensayos de toxicidad utilizando juveniles de charnela recta de Corbicula fluminea. Las concentraciones de las sustancias contaminantes presentaron una gran tendencia geográfica, con valores más altos en la vecindad de las áreas mas densamente pobladas sobre los ríos Reconquista y Luján, disminuyendo sensiblemente en el río San Antonio, y con valores mínimos en el sitio mas remoto ubicado sobre el río Paraná de las Palmas. Este gradiente concuerda muy bien con los patrones de mortalidad, de los juveniles de charnela recta de Corbicula fluminea. Las condiciones ambientales más adversas para los organismos fueron registradas en las aguas de los ríos Reconquista-Lujan (mortalidades de 40 a 93%), mientras que los niveles de respuesta en el río Paraná no difirieron significativamente del control (3.3-2.3% de mortalidad). Ademas la mortalidad de juveniles fue menor en agua superficial (3.3-53%) que en agua de poro (12-73%), y en esta última que en los sedimentos(23-93%). Si bien la toxicidad probablemente fue debida principalmente a los contaminantes disueltos, la mayor concordancia espacial entre las evidencias de contaminación químicas (determinación de tóxicos) y las biológicas (tasas de mortalidad de almejas juveniles) fue registrada en los sedimentos, mientras que las evidencias obtenidas de las muestras de agua de poro y del agua superficial fueron mas heterogéneas y menos concluyentes. Individuos bentónicos y juveniles planctónicos de Corbicula fluminea fueron colectados mensualmente en los ríos Paraná de las Palmas (PP) y San Antonio (SA). Los cambios en la distribución de frecuencias de talla de las almejas de PP a lo largo del periodo de estudio indican claramente una estructura poblacional dinámica, con cohortes anuales claramente definidas y una alta abundancia de reclutas jóvenes durante el único periodo reproductivo centrado sobre los meses de octubre y noviembre. Los parámetros poblacionales estimados mediante el análisis de progresiones modales, aplicando la formula estacionalizada de crecimiento devon Bertalanffy, fueron: largo infinito (La) 32 mm (talla mínima observada: 33mm); constante de crecimiento (K): 0.65; factor de amplitud (C, indicador de variación del crecimiento entre verano e invierno): 0.7; punto de invierno (PI), fracción del año donde el crecimiento es mínimo): 0.5 . El rango de tallas estimadas para los individuos de PP en el primer año de vida fue de 15.3-22.4mm, para el segundo año 23.5-27 mm, y para el tercer año 27.5-29.3 mm. La comparación con los parámetrosFil:Cataldo, Daniel Hugo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Wind Resource Assessment in Building Environment: Benchmarking of Numerical Approaches and Validation with Wind Tunnel Data

ABSTRACT: In the framework of the wind energy network for distributed generation in urban environments for most South American countries, wind resource assessment studies have been carried out in activities to establish a suitable methodology to assess the wind potential in urban environments. Some methodologies are already published in research studies, and the wind tunnel is the most accurate solution to obtain insight into the wind resource when measurements are unavailable, which is the most frequent case. Nevertheless, besides its validity, one cannot disregard the high cost of producing a scaled urban model and access to a wind tunnel. In this sense, this paper compares results from a wind tunnel experiment and different numerical modeling approaches. Two commercial models (WindSim and Wasp Engineering) and one open-source CFD code (OpenFOAM) are used. The results from the modeling simulation concluded that CFD models could achieve lower deviations for the mean wind speed and turbulence intensity when compared with non-CFD models. With such results, CFD modeling is a promising tool for reliably evaluating wind potential in urban environments.info:eu-repo/semantics/publishedVersio

How does Covid-19 disrupt traditional success models: The case of e-learning

This paper questions the prevalent approach in assessing the value of e-learning through the information system model. A recall is made of the evolution of DeLone and McCain model and other theory at the basis of such assessment, namely TAM derived models and performance models. In these years of covid which imposed e-learning on schools, without adequate preparation this examination is more than ever important since it changes the logic of the assessment. The covid19 caused an unvoluntary use of e-learning that questions the validity of prevalent models. An integrated model, which take this aspect into consideration, is proposed in this article, to be validated empirically in a soon future

Reproductive Output and Seasonality of Limnoperna fortunei

Fil: Boltovskoy, Demetrio. Instituto de Ecología. Genética y Evolución de Buenos Aires (IEGEBA). Universidad de Buenos Aires; ArgentinaFil: Morton, Brian. School of Biological Sciences. University of Hong Kong; ChinaFil: Correa, Nancy. Servicio de Hidrografía Naval. Ministerio de Defensa. Escuela de Ciencias del Mar. Instituto Universitario Naval; ArgentinaFil: Cataldo, Daniel. Departamento de Ciencias Biológicas. Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires; ArgentinaFil: Damborenea, María Cristina. División Zoología Invertebrados. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Penchaszadeh, Pablo E.. Museo Argentino de Ciencias Naturales Bernardino Rivadavia; ArgentinaFil: Sylvester, Francisco. Instituto para el Estudio de la Biodiversidad de Invertebrados. Facultad de Ciencias Naturales. Universidad Nacional de Salta; Argentin

Controlled Contamination of Epoxy Composites with PDMS and Removal by Laser Ablation

Surface preparation is critical to the performance of adhesively bonded composites. During manufacturing, minute quantities of mold release compounds are inevitably deposited on faying surfaces and may compromise bond performance. To ensure safety, mechanical fasteners and other crack arrest features must be installed in the bondlines of primary structures, which negates some advantages of adhesively bonded construction. Laser ablation is an automated, repeatable, and scalable process with high potential for the surface preparation of metals and composites in critical applications such as primary airframe structures. In this study, laser ablation is evaluated on composite surfaces for the removal of polydimethylsiloxane (PDMS), a common mold release material. Composite panels were contaminated uniformly with PDMS film thicknesses as low as 6.0 nm as measured by variable angle spectroscopic ellipsometry. Bond performance was assessed by mechanical testing using a 250 F cure, epoxy adhesive and compared with pre-bond surface inspection results. Water contact angle, optically stimulated electron emission, and laser induced breakdown spectroscopy were used to characterize contaminated and laser ablated surfaces. The failure mode obtained from double cantilever beam tests correlated well with surface characterization data. The test results indicated that even low levels of PDMS were not completely removed by laser ablation

Immunomodulatory properties of a γ-aminobutyric acid-enriched strawberry juice produced by levilactobacillus brevis CRL 2013

Gamma-aminobutyric acid (GABA) plays a key role in mammals as the major inhibitory neurotransmitter of the central nervous system. Although GABA may not be able to cross the human blood-brain barrier, it was approved as a food ingredient because of its benefits to the host after oral administration including anti-hypertensive, anti-depressant and anti-inflammatory activities. Considering the current trend toward the development of new functional and natural products and that microbial fermentation is one of the most promising methods to produce this non-protein amino acid, the in situ production of GABA through fermentation of strawberry and blueberry juices by the efficient GABA producer strain, Levilactobacillus brevis (formerly known as Lactobacillus brevis) CRL 2013, was evaluated. A high GABA production (262 mM GABA) was obtained after fermenting strawberry juice supplemented with yeast extract for 168 h, being GABA yield significantly higher in strawberry juices than in the blueberry ones. Thus, GABA-enriched fermented strawberry juice (FSJ) was selected to carry out in vivo and in vitro studies. The in vitro functional analysis of the GABA-enriched FSJ demonstrated its ability to significantly decrease the expression of cox-2 gene in LPS stimulated RAW 264.7 macrophages. In addition, in vivo studies in mice demonstrated that both, L. brevis CRL 2013 and the GABA-enriched FSJ were capable of reducing the levels of peritoneal, intestinal and serum TNF-α, IL-6, and CXCL1, and increasing IL-10 and IFN-γ in mice exposed to an intraperitoneal challenge of LPS. Of note, the GABA-enriched FSJ was more efficient than the CRL 2013 strain to reduce the pro-inflammatory factors and enhance IL-10 production. These results indicated that the CRL 2013 strain exerts anti-inflammatory effects in the context of LPS stimulation and that this effect is potentiated by fermentation. Our results support the potential use of L. brevis CRL 2013 as an immunomodulatory starter culture and strawberry juice as a remarkable vegetable matrix for the manufacture of GABA-enriched fermented functional foods capable of differentially modulating the inflammatory response triggered by TLR4 activation.Fil: Cataldo, Pablo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Villena, Julio Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Elean, Mariano Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Savoy, Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Saavedra, Maria Lucila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Hebert, Elvira Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentin

Molecular analysis of endocrine disruption in hornyhead turbot at wastewater outfalls in southern california using a second generation multi-species microarray.

Sentinel fish hornyhead turbot (Pleuronichthysverticalis) captured near wastewater outfalls are used for monitoring exposure to industrial and agricultural chemicals of ~ 20 million people living in coastal Southern California. Although analyses of hormones in blood and organ morphology and histology are useful for assessing contaminant exposure, there is a need for quantitative and sensitive molecular measurements, since contaminants of emerging concern are known to produce subtle effects. We developed a second generation multi-species microarray with expanded content and sensitivity to investigate endocrine disruption in turbot captured near wastewater outfalls in San Diego, Orange County and Los Angeles California. Analysis of expression of genes involved in hormone [e.g., estrogen, androgen, thyroid] responses and xenobiotic metabolism in turbot livers was correlated with a series of phenotypic end points. Molecular analyses of turbot livers uncovered altered expression of vitellogenin and zona pellucida protein, indicating exposure to one or more estrogenic chemicals, as well as, alterations in cytochrome P450 (CYP) 1A, CYP3A and glutathione S-transferase-α indicating induction of the detoxification response. Molecular responses indicative of exposure to endocrine disruptors were observed in field-caught hornyhead turbot captured in Southern California demonstrating the utility of molecular methods for monitoring environmental chemicals in wastewater outfalls. Moreover, this approach can be adapted to monitor other sites for contaminants of emerging concern in other fish species for which there are few available gene sequences

Detection of Intranasally Delivered Bone Marrow-Derived Mesenchymal Stromal Cells in the Lesioned Mouse Brain: A Cautionary Report

Bone marrow-derived mesenchymal stromal cells (MSCs) hold promise for autologous treatment of neuropathologies. Intranasal delivery is relatively noninvasive and has recently been reported to result in transport of MSCs to the brain. However, the ability of MSCs to migrate from nasal passages to sites of neuropathology and ultimately survive has not been fully examined. In this paper, we harvested MSCs from transgenic mice expressing enhanced green fluorescent protein (cells hereafter referred to as MSC-EGFP) and delivered them intranasally to wild-type mice sustaining mechanical lesions in the striatum. Using fluorescent, colorimetric, and ultrastructural detection methods, GFP-expressing cells were undetectable in the brain from 3 hours to 2 months after MSC delivery. However, bright autofluorescence that strongly resembled emission from GFP was observed in the olfactory bulb and striatum of lesioned control and MSC-EGFP-treated mice. In a control experiment, we directly implanted MSC-EGFPs into the mouse striatum and detected robust GFP expression 1 and 7 days after implantation. These findings suggest that—under our conditions—intranasally delivered MSC-EGFPs do not survive or migrate in the brain. Furthermore, our observations highlight the necessity of including appropriate controls when working with GFP as a cellular marker