Co-infections and multiple stressors in fish

Fish are typically exposed to multiple physical, chemical and biological stressors. The cumulative impact of co-infections between parasites, bacteria, viruses and (a)biotic environmental pressures may trigger complex interactions, eliciting different pathological and immunological outcomes than those classically assessed. New cross-disciplinary studies attempt to measure the impact of environmental stressors in modulating the host response to pathogens. Scientific advances are needed to reduce pressure on natural populations, improve fish stock management, and to design more efficient diagnostic tools or vaccination strategies. An EAFP-promoted workshop, held on 10th September 2019 in Porto, Portugal, was dedicated to sharing research experiences on the interaction between heterogenous pathogens and multiple stressors in fish. The workshop involved around 200 attendants, opened by a keynote talk (Fast), and followed by a further twelve oral presentations, including three in the format of lash poster presentations. Contributions illustrated cross-disciplinary approaches to study complex host-pathogen and stressors interactions

Molecular tracing of viral diseases in aquaculture

Molecular Tracing of Viral Diseases in Aquaculture = Traçage Moléculaire des Maladies Virales en Aquaculture : Colloque, Montpellier (FRA), 2015/01/27-29International audienc

Chemical Functionalization of Carbon Supported Metal Nanoparticles by Ionic Conductive Polymer via the "Grafting From" Method

International audiencefavor Platinum nanoparticles (Pt-NPs) supported on carbon powder are prepared via a water-in-oil microemulsion method and modified by a disulfide aryl initiator either by a postgrafting method or by a one pot in situ "grafting from" method. It is shown that the grafting of the disulfide derivation initiator is quantitative from 2 to 10 wt %, independently on the method. ATRP of sodium styrene sulfonate (SSNa) has then been performed from the initiator molecules grafted on the surface of the Pt-NPs supported on an electron conductive porous substrate and electrochemical measurements are performed. Although the polymerization reaction was not total (60%), derivatization of the Pt-NPs-initiator/C with different polymerization densities and polymer molecular weights are obtained. Electrodes fabricated from such nanocomposites shows enhanced performances toward the oxygen reduction reaction. Higher activity is obtained with lower polymerization density and higher polymer molecular weight. The enhancement of activity is attributed to the difference in hydrophilic character between the polymer skeleton (which could favor oxygen transport toward active sites) and the pendant sulfonic acid groups (which favor the proton transport toward the active sites)

Recherche des critères microsismiques d'évaluation d'un danger de coups de terrains

Within the Provence opération Unit (France), microseismic remote monitoring is integrated within a research strategy bearing on areas submitted to dynamic phenomena risks. The purpose of this study is to characterise and analyse the induced microseismic activity during the opération of deep sites, in order to obtain identification criteria for the zones likely to generate such phenomena. The detailed study of the space distribution of microseismic focuses enables consistent corrélations to be demonstrated between the localization of the focuses, the changes in the state of stresses in the massif during the mining opération and the configuration of exploitation. The results hâve opened interesting perspectives into the analysis of pressure rockburst risks, by microseismic listening

Integrated engineering-geological and numerical approach applied to the large Buyukcekmece (Turkey) landslide for evaluating earthquake-induced effects

The Buyukcekmece landslide, W of Istanbul (Turkey), was selected for MARSite project (New directions in seismic hazard assessment through focused Earth observation in the Marmara Super-site) as case-study of earthquake-induced landslides. The local seismic response of the landslide slope was analyzed reconstructing a detailed engineering-geological model. Geophysical measurements were carried out to constrain geometries and attribute mechanical properties. A multisensor in-hole monitoring system and a local GPS-RTK network were installed since October 2014. The collected records show piezometer trends related to seasonal as well to intense rainfalls and confirm a continuous EW movement of the landslide; 65 recorded earthquakes demonstrate an amplification due to the landslide mass. Slope stability was analyzed through an unconventional pseudostatic approach by considering different seismic waveforms. Stress-strain numerical models indicate that local seismic response is jointed to the geological setting and the interaction between seismic waves and slope is not negligible to evaluate possible landslide reactivations

Comprehensive analysis of the local seismic response in the complex Buyukcekmece landslide area (Turkey) by engineering-geological and numerical modelling

Multi-risk management requires a strong comprehension of possible effects induced by natural hazardous events. In this regard, landslides triggering due to earthquakes results from complex interactions between seismic waves and slopes. Multidisciplinary approaches can significantly contribute to better understand such interactions. The large Buyukcekmece landslide (about 1500 m wide and 1830 m long) located in Turkey (Avcilar peninsula), about 15 km northward from the North Anatolian Fault Zone (NAFZ), was selected as case-study in the framework of the European project "MARSite - Marmara Supersite: new directions in seismic hazard assessment through focused Earth observation in the Marmara Supersite". The Avcilar area was recently affected by the 17th August 1999 Mw 7.4 Kocaeli and by the 12th November Mw 7.2 Duzce earthquakes. The Buyukcekmece landslide involves upper Oligocene to lower Miocene deposits, consisting of silty clays, tuffs and sands. No earthquake-induced re-activations are testified so far but the landslide area was interested by a very intense urbanization during the last decade. A detailed engineering-geological model for the local seismic response of the Buyukcekmece landslide slope was constructed based on geophysical measurements, data from a multisensor in-hole monitoring system and stress-strain numerical modelling. Several tens of earthquakes were recorded from October 2014 to May 2015 in the landslide site by considering in-hole and surface data. The reliability of the local seismic response obtained by numerical modelling respect to the empirically derived one was checked in terms of both site-to-reference spectral ratios and transfer function between surface and downhole sites inside the landslide mass. The 2D numerical amplification functions confirm that the local seismic response is a consequence of the complex geological setting of the landslide slope while no relevant amplification effects can be referred to topographic features. Based on these results, the interaction between seismic waves and the Buyukcekmece landslide slope cannot be neglected to evaluate the possibility of future landslide re-activations. (C) 2017 Elsevier B.V. All rights reserved

How a multidisciplinary work in the Marmara Supersite, related to Earthquake induced landslide hazard, was successful carried out

Seismic risk is the first source of life and economical losses in Turkey. Located on the North Anatolian fault line, Istanbul and its surrounding areas have been hit by an estimated 120 earthquakes over the last 2,000 years, according to the Istanbul municipality's Disaster Coordination Center. Besides the seismic threat, landslides in Turkey constitute an important source of loss. The 1999 Earthquake caused extensive landslides while tsunami effects were observed during the post-event surveys in several places along the coasts of the Izmit bay (Altinok et al., 2001). The seismic landslide hazards have received considerable attention in recent years, but quantitative knowledge on seismic landslide phenomena is still fragmentary, databases with high quality observational data are lacking, and those collateral seismic geohazards are clearly challenging both the scientific community and prevention authorities. These phenomena call for further collaborative researches aiming eventually to enhance preparedness and crisis management. As one of the three Supersite concept FP7 (EU’s Seventh Framework Programme for Research) projects dealing with long term high level monitoring of major natural hazards at the European level, the MARsite project (Nov 2012-Nov 2015) assemble research groups in a comprehensive monitoring activity developed in the Sea of Marmara Region, one of the most densely populated parts of Europe and rated at high seismic risk level since the 1999 Izmit and Duzce devastating earthquakes. Supersites is an initiative of the geohazard scientific community. The Supersites provide access to space borne and in-situ geophysical data of selected sites prone to earthquake, volcano or other hazards. The 6th Work Package of MARsite project gathers 9 research groups to study earthquake-induced landslides focusing on two sub-regional areas of high interest. First, the Cekmece-Avcilar peninsula, located westwards of Istanbul, is a highly urbanized concentrated landslide prone area (Duman et al., 2006), showing high susceptibility to both rainfalls while affected by very significant seismic site effects (Ergin et al., 2004; Picozzi et al., 2009). Second, the off-shore entrance of the Izmit Gulf, close to the termination of the surface rupture of the 1999 earthquake, that shows an important slump mass facing the Istanbul coastline. A multidisciplinary research program based on pre-existing studies has been designed with objectives and tasks linked to constrain and tackle progressively some challenging issues related to data integration, modeling, and monitoring. For the on-shore area, this program included the refined analysis of the seismic site response, the installation of a permanent multi-parameter ground monitoring of a representative unstable slope as well as the in-depth slope stability analysis based on the stress-strain dynamic numerical modelling approach. After refining the landslide inventory of the peninsula, one landslide (Beylikdüzü landslide) was chosen as pilot site as it resulted the most dangerous due to the highest susceptibility to seismically-induced re-activation and to the highest exposition of buildings and infrastructures referred to the last decade (i.e. after the 1999 Izmit earthquake occurrence). In this landslide area were carried out geophysical campaigns and a field permanent multi-parameter observatory was set up, composed of GPS-RTK, borehole- and surface-seismometers thermometer, rain-gauge, moisture, etc.. Hyperspectral and Dinsar imagery technologies are also deployed to complete inventory and observational information. Concerning, the modelling of the seismic response and displacements of the pilot landslide, the first step was to have an adequate engineering-geological model. A first engineering-geological model was reconstructed on the basis of extensive geological and geomorphological field campaign and a vast drilling program undertaken by the Istanbul Metropolitan Area. Based on a detailed engineering-geological model of the landslide slope, a not-conventional pseudostatic slope stability analysis (Figure 1) was performed by considering a pseudostatic force distribution within the landslide mass according to a specific wave form instead of a conventional constant pseudostatic force. Numerical simulations of the seismic response in the landslide slope were also performed aiming at evaluating the role of geological and structural setting of the slope on the landslide displacements in case of expected earthquakes. Multi-parameter monitoring with its long-term time series will be an important tool to validate numerical models and simulations and set up an experimental early warning system for earthquake and rainfall induced landslide