Living on a trophic subsidy: Algal quality drives an upper-shore herbivore’s consumption, preference and absorption but not growth rates

Indexación: Scopus.The transfer of seaweeds from subtidal bottoms to nearby intertidal rocky shores is a common but often overlooked phenomenon. Freshly detached seaweeds often represent critical trophic subsidies for herbivores living in upper-shore rocky intertidal areas, such as the marine snail Diloma nigerrima. This species relies on three species of seaweeds for food and displays feeding strategies to deal with a resource that is scarce and at times unpredictable. This study focused on the nutritional quality of freshly detached algae (Durvillaea antarctica, Lessonia spicata and Lessonia trabeculata) and measured Diloma nigerrima’s algal consumption rates in trials with and without choice. Absorption efficiency and growth of individual snails fed on each alga were also measured. Durvillaea antarctica had the highest nutritional quality and was the most consumed algae in both single and multiple-choice trials. Absorption efficiency was also highest for D. antarctica but growth rates of snails fed with this species were similar to those fed with the other algae. Combined, these results suggest that D. nigerrima has the ability to discriminate among seaweeds based on their nutritional quality. A potential increase in oxygen uptake when D. nigerrima is consuming the preferred food item is also proposed as a plausible hypothesis to explain the mismatch between snails’ preference and growth rate. These results aim to guide further studies on trophic subsidies and their role in coastal systems. © 2018 Quintanilla-Ahumada et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.https://journals.plos.org/plosone/article?id=10.1371/journal.pone.019612

Seismotectonic characterization of the Becerreá area (NW Spain)

The NW sector of the Iberian Peninsula has been classically considered as a seismically stable area, with only dispersed and low-magnitude activity. Around the village of Becerreá (Lugo) a significant concentration of earthquakes is observed. Since the beginning of instrumental record in 1979, seven seismic crisis have been reported in that zone, including 14 events of magnitude >4 and a larger event of magnitude 5.1mbLg (VII EMS) in 1997. Even if this seismicity is to be related to the general compressive regime between Africa and Eurasia, the seismotectonic characterization of the area is still controversial, as the different hypotheses considered are based on insufficiently accurate data. New insights to the problem are discussed here, coming from the deployment of a seismic portable network between 1999 and 2002, which has provided new accurate seismic data. The corresponding events are distributed around a subvertical axis, reaching a depth of 12km, and epicentres tend to concentrate beneath the intersection of the main Becerreá fault and secondary, ENE/WSW oriented faults. This intersection structure is thus interpreted as being responsible for the relatively high level of seismic activity over the area

Pharmacological iron-chelation as an assisted nutritional immunity strategy against Piscirickettsia salmonis infection

Indexación ScopusSalmonid Rickettsial Septicaemia (SRS), caused by Piscirickettsia salmonis, is a severe bacterial disease in the Chilean salmon farming industry. Vaccines and antibiotics are the current strategies to fight SRS; however, the high frequency of new epizootic events confirms the need to develop new strategies to combat this disease. An innovative opportunity is perturbing the host pathways used by the microorganisms to replicate inside host cells through host-directed antimicrobial drugs (HDAD). Iron is a critical nutrient for P. salmonis infection; hence, the use of iron-chelators becomes an excellent alternative to be used as HDAD. The aim of this work was to use the iron chelator Deferiprone (DFP) as HDAD to treat SRS. Here, we describe the protective effect of the iron chelator DFP over P. salmonis infections at non-antibiotic concentrations, in bacterial challenges both in vitro and in vivo. At the cellular level, our results indicate that DFP reduced the intracellular iron content by 33.1% and P. salmonis relative load during bacterial infections by 78%. These findings were recapitulated in fish, where DFP reduced the mortality of rainbow trout challenged with P. salmonis in 34.9% compared to the non-treated group. This is the first report of the protective capacity of an iron chelator against infection in fish, becoming a potential effective host-directed therapy for SRS and other animals against ferrophilic pathogens. © 2020, The Author(s).https://veterinaryresearch.biomedcentral.com/articles/10.1186/s13567-020-00845-

Seismicity, seismotectonics and seismic hazard in the Cantabrian region: new data from the SISCAN and MISTERIOS dense seismic networks (2014-2020)

X Congreso Geológico de España, 5-7 Julio 2021, Vitoria - GasteizLa región Cantábrica, al tratarse de una zona tradicionalmente considerada de baja sismicidad, ha suscitado menor atención que otras regiones sísmicamente más activas. Los nuevos datos recogidos por las redes sísmicas temporales implantadas en el marco de los proyectos SISCAN y MISTERIOS (2014-2020) han permitido mejorar el conocimiento acerca de la actividad sísmica de la zona. Durante el periodo del estudio, de casi seis años, se desplegaron más de 50 estaciones en la Región Cantábrica y norte de la Cordillera Ibérica. La densidad de estaciones y la geometría regular de estas redes han permitido registrar una sismicidad significativa. Se han localizado más de más de 1200 terremotos y se han calculado más de 60 mecanismos focales, en una región dónde apenas existían este tipo de datos. Los eventos localizados con mayor precisión y los mecanismos focales calculados se utilizaron para avanzar en la interpretación sismotectónica, con la identificación de las principales fallas activas. Por último, se ha llevado a cabo una evaluación de la peligrosidad sísmica de la región cantábrica y del Pirineo occidental. Para ello se ha abordado una modelización probabilista de la peligrosidad sísmica en términos de aceleración pico (PGA) y de aceleraciones espectrales (SA (T)) para un periodo de retorno de 475 años.The present-day seismicity in the Cantabrian region (North of Iberia) is not well known due to the limited coverage of stations from permanent seismic network in the area. Being an area traditionally considered of low seismicity, it has attracted less attention than other seismically more active regions, such as the southeast and northwest of the Iberian Peninsula, or the Pyrenean area. The new data collected by the temporary seismic networks implemented during the SISCAN and MISTERIOS projects (2014-2020) have allowed us to improve our knowledge about the seismic activity in the area. During the study period, for almost six years, a seismic network of more than 50 stations was deployed in the Cantabrian Region and the northern Iberian Chain. The density of stations and the regular geometry of these seismic net-works have allowed us to register a significant seismic activity. More than 1200 earthquakes have been located and more than 60 focal mechanisms have been calculated in a region where such data was hard-ly available. The events located with the greatest precision and the calculated focal mechanisms were used to improve the seismotectonic interpretation, with the identification of the main active faults. Final-ly, an evaluation of the seismic hazard in the Cantabrian region and the western Pyrenees has been carried out. To this end, a probabilistic modeling of the seismic hazard in terms of peak ground acceleration (PGA) and spectral acceleration (SA (T)) has been addressed for a return period of 475 years

Continuous GPS stations deployment in the Topo-Iberia Project framework

Topo-Iberia es un proyecto financiado por el Ministerio de Educación y Ciencia de España. Su principal objetivo es comprender las interacciones entre los procesos profundos, superficiales y atmosféricos integrando datos geológicos, geofísicos y geodéticos. El proyecto se centrará en tres zonas principales de interés en la Península Ibérica: los bordes N y S de la Placa Ibérica (incluyendo el N de Marruecos) y su núcleo central intermedio. Presentamos las actividades preliminares realizadas por el subgrupo GPS de Topo-Iberia con el fin de desplegar una nueva red continua de GPS. La intención es complementar las redes CGPS continuas existentes (p.e. ROA; ERGPS) incrementado la cobertura espacial en España y N de Marruecos. Una vez seleccionados los emplazamientos de las nuevas estaciones, el objetivo es que se encuentren en pleno funcionamiento la primavera de 2008. Se han descargado conjuntos de datos CGPS de servidores de distintas instituciones sobre los que se ha realizado un procesado inicial que sirva como control de calidad. Como algunas de las estaciones actualmente disponibles no siguen los estrictos procedimientos de estabilidad dictados por IGS/EUREF, estamos evaluando sus resultados mediante análisis de series temporales para decidir cuales se pueden incluir como estaciones complementarias de la red Topo-Iberia.Topo-Iberia is a Spanish Research Council funded project. Its main objective is to understand the interactions between deep, shallow and atmospheric processes, integrating geological, geophysical, geodetic and geo-technological research activities. The project will focus in three main areas of interest in the Iberian Peninsula: Northern and Southern borders of the Iberian micro-plate (taking into account the Northern part of Morocco), and its central core. We present the preliminary steps that the Topo- Iberia GPS working group is undergoing in order to deploy a new Continuous GPS Network. We are trying to complement the existing and functioning CGPS Networks (e.g. ROA; ERGPS) by increasing the spatial coverage across Spain and Northern Morocco. The places for the new locations have been chosen and all stations should be working in the spring 2008. A set of available CGPS data files has been downloaded from different institutional servers. A preliminary data analysis has been performed for geodetic quality control. Since some of the existing CGPS stations have been installed without following strict IGS/EUREF procedures for the stability of the monuments, we are evaluating their performance through the time series analysis, in order to decide whether to include them as complementing stations to our network.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEMinisterio de Ciencia e Innovación (MICINN)CONSOLIDER TOPO-Iberiapu

Deep-sequencing reveals broad subtype-specific HCV resistance mutations associated with treatment failure

A percentage of hepatitis C virus (HCV)-infected patients fail direct acting antiviral (DAA)-based treatment regimens, often because of drug resistance-associated substitutions (RAS). The aim of this study was to characterize the resistance profile of a large cohort of patients failing DAA-based treatments, and investigate the relationship between HCV subtype and failure, as an aid to optimizing management of these patients. A new, standardized HCV-RAS testing protocol based on deep sequencing was designed and applied to 220 previously subtyped samples from patients failing DAA treatment, collected in 39 Spanish hospitals. The majority had received DAA-based interferon (IFN) a-free regimens; 79% had failed sofosbuvir-containing therapy. Genomic regions encoding the nonstructural protein (NS) 3, NS5A, and NS5B (DAA target regions) were analyzed using subtype-specific primers. Viral subtype distribution was as follows: genotype (G) 1, 62.7%; G3a, 21.4%; G4d, 12.3%; G2, 1.8%; and mixed infections 1.8%. Overall, 88.6% of patients carried at least 1 RAS, and 19% carried RAS at frequencies below 20% in the mutant spectrum. There were no differences in RAS selection between treatments with and without ribavirin. Regardless of the treatment received, each HCV subtype showed specific types of RAS. Of note, no RAS were detected in the target proteins of 18.6% of patients failing treatment, and 30.4% of patients had RAS in proteins that were not targets of the inhibitors they received. HCV patients failing DAA therapy showed a high diversity of RAS. Ribavirin use did not influence the type or number of RAS at failure. The subtype-specific pattern of RAS emergence underscores the importance of accurate HCV subtyping. The frequency of “extra-target” RAS suggests the need for RAS screening in all three DAA target regions

Observation of inverse Compton emission from a long γ-ray burst.

Long-duration γ-ray bursts (GRBs) originate from ultra-relativistic jets launched from the collapsing cores of dying massive stars. They are characterized by an initial phase of bright and highly variable radiation in the kiloelectronvolt-to-megaelectronvolt band, which is probably produced within the jet and lasts from milliseconds to minutes, known as the prompt emission1,2. Subsequently, the interaction of the jet with the surrounding medium generates shock waves that are responsible for the afterglow emission, which lasts from days to months and occurs over a broad energy range from the radio to the gigaelectronvolt bands1-6. The afterglow emission is generally well explained as synchrotron radiation emitted by electrons accelerated by the external shock7-9. Recently, intense long-lasting emission between 0.2 and 1 teraelectronvolts was observed from GRB 190114C10,11. Here we report multi-frequency observations of GRB 190114C, and study the evolution in time of the GRB emission across 17 orders of magnitude in energy, from 5 × 10-6 to 1012 electronvolts. We find that the broadband spectral energy distribution is double-peaked, with the teraelectronvolt emission constituting a distinct spectral component with power comparable to the synchrotron component. This component is associated with the afterglow and is satisfactorily explained by inverse Compton up-scattering of synchrotron photons by high-energy electrons. We find that the conditions required to account for the observed teraelectronvolt component are typical for GRBs, supporting the possibility that inverse Compton emission is commonly produced in GRBs

Seismotectonic constraints at the western edge of the Pyrenees: Aftershock series monitoring of the 2002 February 21, 4.1 Lg earthquake

Seismic data recorded from a temporary network deployed at the western edge of the Pyrenees is used to study the aftershocks series following a magnitude 4.1 earthquake that took place on 2002 February 21, to the NW of Pamplona city. Aftershock determinations showed events distributed between 1 and 4 km depth in a small active area of about 4 km2, E-W oriented delineating the southern sector of the Aralar thrust unit. This seismogenic feature is supported by focal solutions showing a consistent E-W nodal plane with normal faulting following the main strike-slip rupture. The Aralar structure with its shallow activity may be interpreted as a conjugate system of the NE-SW deep-seated Pamplona active fault nearby. Cross-correlation techniques and relative location of event clusters further constrained the epicentral domain to 2 km long and 1 km wide. Statistical relations and parameters established indicate a rather low b-value of 0.8 for the Gutenberg-Richter distribution, denoting a region of concentrated seismicity, and a P-parameter of 0.9 for the Omori's law corresponding to a low decay of the aftershock activity in this area. More than 100 aftershocks were accurately located in this high-resolution experiment, whereas only 13 of them could be catalogued by the permanent agencies in the same period, due to a much sparser distribution. The results enhance the importance of using dense temporary networks to infer relevant seismotectonic and hazard constraints. © 2006 The Authors Journal compilation © 2006 RAS.This work was carried out with the support of the MARCONI (REN2001-1734) project from the Spanish MCYT. MR and CL benefited from a PhD grant from the Spanish MCYT. We would like to thank to the responsible of the IGN, RENASS, OMP and CEA databases for sharing the seismological data used in this study.Peer Reviewe