Modeling the interannual variability in Maipo and Rapel river plumes off central Chile

River plumes have a direct influence on coastal environments, impacting coastal planktonic and benthic communities, including fishery resources. In general, the main drivers of river plume dynamics are the river discharge and the alongshore wind stress, whereas the tides and topography play a secondary role. In central Chile, rivers flowing into the eastern Pacific have a relatively short path on land, with a high slope and a mixed snow–rain regime. This study aims to understand the interannual variability in the plumes of the Maipo and Rapel rivers in the coastal/shelf area off central Chile and their influence on local ocean dynamics. We used the Coastal and Regional Ocean Community (CROCO) model, with 1 km horizontal resolution and 20 sigma levels, to simulate the ocean dynamics for the period 2003–2011. The results show that the plume's area coverage and coastal ocean salinity are strongly correlated with the river discharges. The predominant northeastward winds control the plumes' orientation toward the northwest. However, episodes of southeastward winds in winter can reverse the plumes' direction, promoting their attachment to the coast and southward transport. Results also show a salification trend linked to the severe droughts hitting central Chile during the studied period. This salification determines a change in local dynamics which could be more frequent in future scenarios of climate change with a significant lack of rain and river discharges along central Chile.</p

Continental shelf off northern Chilean Patagonia: A potential risk zone for the onset of Alexandrium catenella toxic bloom?

Harmful Algal Blooms (HAB) pose a severe socio-economic problem worldwide. The dinoflagellate species Alexandrium catenella produces potent neurotoxins called saxitoxins (STXs) and its blooms are associated with the human intoxication named Paralytic Shellfish Poisoning (PSP). Knowing where and how these blooms originate is crucial to predict blooms. Most studies in the Chilean Patagonia, were focused on coastal areas, considering that blooms from the adjacent oceanic region are almost non-existent. Using a combination of field studies and modelling approaches, we first evaluated the role of the continental shelf off northern Chilean Patagonia as a source of A. catenella resting cysts, which may act as inoculum for their toxic coastal blooms. This area is characterized by a seasonal upwelling system with positive Ekman pumping during spring-summer, and by the presence of six major submarine canyons. We found out that these submarine canyons increase the vertical advection of bottom waters, and thus, significantly enhance the process of coastal upwelling. This is a previously unreported factor, among those involved in bloom initiation. This finding put this offshore area at high risk of resuspension of resting cysts of A. catenella. Here, we discuss in detail the physical processes promoting this resuspension.Harmful Algal Blooms (HAB) pose a severe socio-economic problem worldwide. The dinoflagellate species Alexandrium catenella produces potent neurotoxins called saxitoxins (STXs) and its blooms are associated with the human intoxication named Paralytic Shellfish Poisoning (PSP). Knowing where and how these blooms originate is crucial to predict blooms. Most studies in the Chilean Patagonia, were focused on coastal areas, considering that blooms from the adjacent oceanic region are almost non-existent. Using a combination of field studies and modelling approaches, we first evaluated the role of the continental shelf off northern Chilean Patagonia as a source of A. catenella resting cysts, which may act as inoculum for their toxic coastal blooms. This area is characterized by a seasonal upwelling system with positive Ekman pumping during spring-summer, and by the presence of six major submarine canyons. We found out that these submarine canyons increase the vertical advection of bottom waters, and thus, significantly enhance the process of coastal upwelling. This is a previously unreported factor, among those involved in bloom initiation. This finding put this offshore area at high risk of resuspension of resting cysts of A. catenella. Here, we discuss in detail the physical processes promoting this resuspension.Postprint2,35

Burkholderia cenocepacia BC2L-C Is a Super Lectin with Dual Specificity and Proinflammatory Activity

Lectins and adhesins are involved in bacterial adhesion to host tissues and mucus during early steps of infection. We report the characterization of BC2L-C, a soluble lectin from the opportunistic pathogen Burkholderia cenocepacia, which has two distinct domains with unique specificities and biological activities. The N-terminal domain is a novel TNF-α-like fucose-binding lectin, while the C-terminal part is similar to a superfamily of calcium-dependent bacterial lectins. The C-terminal domain displays specificity for mannose and l-glycero-d-manno-heptose. BC2L-C is therefore a superlectin that binds independently to mannose/heptose glycoconjugates and fucosylated human histo-blood group epitopes. The apo form of the C-terminal domain crystallized as a dimer, and calcium and mannose could be docked in the binding site. The whole lectin is hexameric and the overall structure, determined by electron microscopy and small angle X-ray scattering, reveals a flexible arrangement of three mannose/heptose-specific dimers flanked by two fucose-specific TNF-α-like trimers. We propose that BC2L-C binds to the bacterial surface in a mannose/heptose-dependent manner via the C-terminal domain. The TNF-α-like domain triggers IL-8 production in cultured airway epithelial cells in a carbohydrate-independent manner, and is therefore proposed to play a role in the dysregulated proinflammatory response observed in B. cenocepacia lung infections. The unique architecture of this newly recognized superlectin correlates with multiple functions including bacterial cell cross-linking, adhesion to human epithelia, and stimulation of inflammation

O Bom, o Mau e o Feio: Um enfoque pragmático para a revisão de uma ética e uma política para Internet

The article stems from a broader ongoing research project on Internet, Global Constitutionalism and Ethics. We attempt to brisk up traditional ethical thinking against the background of urgent questions concerning the Internet. By revisiting the perspective of cosmopolitanism that was inspired by Kant's thesis of a universal rationality, reflecting upon Hanna Arendt's critical analysis of moral claims and political outcome, and building on Capurro's "net ethics", we introduce a perspective aiming at an intercultural understanding that might guide our actions in global politics in times of the so called digital era. The article advances the idea by Hannah Arendt that a concrete example as such has moral relevance and therefore makes a case to foster this approach using "best practices" as explicit examples to follow.Este artículo deriva de un proyecto de investigación mayor sobre Internet, Constitucionalismo Global y Ética. En él intentamos avivar el pensamiento ético tradicional a la luz de preguntas urgentes relativas a Internet. Pasamos revista a la perspectiva del cosmopolitismo, reflexionando sobre el análisis crítico de aseveraciones morales y los resultados políticos, y, finalmente, construyendo sobre la "net ethics" de Capurro, presentamos una perspectiva que apunta a un entendimiento intercultural capaz de guiar nuestras acciones en la política global en tiempos de la denominada "era digital". El artículo utiliza de idea de Hannah Arendt que afirma que un ejemplo concreto, como tal, tiene relevancia moral y, por ende, propone este enfoque relativo a las "mejores prácticas" como un ejemplos explícitos a seguir.Este artigo deriva de um projeto de investigação maior sobre Internet, Constitucionalismo Global e Ética. Nele tentamos avivar o pensamento ético tradicional à luz de preguntas urgentes relativas à Internet. Passamos em revista a perspectiva do cosmopolitismo, refletindo sobre a análise crítica de asseverações morais e os resultados políticos, e, finalmente, construindo sobre a "net ethics" de Capurro, apresentamos uma perspectiva que aponta para um entendimento intercultural capaz de guiar nossas ações na política global em tempos da denominada "era digital". O artigo utiliza da ideia de Hannah Arendt que afirma que um exemplo concreto, como tal, tem relevância moral e, por fim, propõe este enfoque relativo às "melhores práticas" como um exemplos explícitos a seguir.  

O Bom, o Mau e o Feio: Um enfoque pragmático para a revisão de uma ética e uma política para Internet

The article stems from a broader ongoing research project on Internet, Global Constitutionalism and Ethics. We attempt to brisk up traditional ethical thinking against the background of urgent questions concerning the Internet. By revisiting the perspective of cosmopolitanism that was inspired by Kant's thesis of a universal rationality, reflecting upon Hanna Arendt's critical analysis of moral claims and political outcome, and building on Capurro's "net ethics", we introduce a perspective aiming at an intercultural understanding that might guide our actions in global politics in times of the so called digital era. The article advances the idea by Hannah Arendt that a concrete example as such has moral relevance and therefore makes a case to foster this approach using "best practices" as explicit examples to follow.Este artículo deriva de un proyecto de investigación mayor sobre Internet, Constitucionalismo Global y Ética. En él intentamos avivar el pensamiento ético tradicional a la luz de preguntas urgentes relativas a Internet. Pasamos revista a la perspectiva del cosmopolitismo, reflexionando sobre el análisis crítico de aseveraciones morales y los resultados políticos, y, finalmente, construyendo sobre la "net ethics" de Capurro, presentamos una perspectiva que apunta a un entendimiento intercultural capaz de guiar nuestras acciones en la política global en tiempos de la denominada "era digital". El artículo utiliza de idea de Hannah Arendt que afirma que un ejemplo concreto, como tal, tiene relevancia moral y, por ende, propone este enfoque relativo a las "mejores prácticas" como un ejemplos explícitos a seguir.Este artigo deriva de um projeto de investigação maior sobre Internet, Constitucionalismo Global e Ética. Nele tentamos avivar o pensamento ético tradicional à luz de preguntas urgentes relativas à Internet. Passamos em revista a perspectiva do cosmopolitismo, refletindo sobre a análise crítica de asseverações morais e os resultados políticos, e, finalmente, construindo sobre a "net ethics" de Capurro, apresentamos uma perspectiva que aponta para um entendimento intercultural capaz de guiar nossas ações na política global em tempos da denominada "era digital". O artigo utiliza da ideia de Hannah Arendt que afirma que um exemplo concreto, como tal, tem relevância moral e, por fim, propõe este enfoque relativo às "melhores práticas" como um exemplos explícitos a seguir.