36 research outputs found

    Ocean Noise

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    Scientific and societal concern about the effects of underwater sound on marine ecosystems is growing. While iconic megafauna was of initial concern, more and more taxa are being included. Some countries have joined in multi-national initiatives to measure, monitor and mitigate environmental impacts of ocean noise at large, trans-boundary spatial scales. Approaches to regulating ocean noise change as new scientific evidence becomes available, but may also differ by country. The OCEANOISE conference series has provided a platform for the exchange of scientific results, management approaches, research needs, stakeholder concerns, etc. Attendees have represented various sectors, including academia, offshore industry, defence, NGOs, consultants and government regulators. The published articles in the Special Issue cover a range of topics and applications central to ocean noise

    EVOLUTION OF THE SUBCONTINENTAL LITHOSPHERE DURING MESOZOIC TETHYAN RIFTING: CONSTRAINTS FROM THE EXTERNAL LIGURIAN MANTLE SECTION (NORTHERN APENNINE, ITALY)

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    Our study is focussed on mantle bodies from the External Ligurian ophiolites, within the Monte Gavi and Monte Sant'Agostino areas. Here, two distinct pyroxenite-bearing mantle sections were recognized, mainly based on their plagioclase-facies evolution. The Monte Gavi mantle section is nearly undeformed and records reactive melt infiltration under plagioclase-facies conditions. This process involved both peridotites (clinopyroxene-poor lherzolites) and enclosed spinel pyroxenite layers, and occurred at 0.7–0.8 GPa. In the Monte Gavi peridotites and pyroxenites, the spinel-facies clinopyroxene was replaced by Ca-rich plagioclase and new orthopyroxene, typically associated with secondary clinopyroxene. The reactive melt migration caused increase of TiO2 contents in relict clinopyroxene and spinel, with the latter also recording a Cr2O3 increase. In the Monte Gavi peridotites and pyroxenites, geothermometers based on slowly diffusing elements (REE and Y) record high temperature conditions (1200-1250 °C) related to the melt infiltration event, followed by subsolidus cooling until ca. 900°C. The Monte Sant'Agostino mantle section is characterized by widespread ductile shearing with no evidence of melt infiltration. The deformation recorded by the Monte Sant'Agostino peridotites (clinopyroxene-rich lherzolites) occurred at 750–800 °C and 0.3–0.6 GPa, leading to protomylonitic to ultramylonitic textures with extreme grain size reduction (10–50 μm). Compared to the peridotites, the enclosed pyroxenite layers gave higher temperature-pressure estimates for the plagioclase-facies re-equilibration (870–930 °C and 0.8–0.9 GPa). We propose that the earlier plagioclase crystallization in the pyroxenites enhanced strain localization and formation of mylonite shear zones in the entire mantle section. We subdivide the subcontinental mantle section from the External Ligurian ophiolites into three distinct domains, developed in response to the rifting evolution that ultimately formed a Middle Jurassic ocean-continent transition: (1) a spinel tectonite domain, characterized by subsolidus static formation of plagioclase, i.e. the Suvero mantle section (Hidas et al., 2020), (2) a plagioclase mylonite domain experiencing melt-absent deformation and (3) a nearly undeformed domain that underwent reactive melt infiltration under plagioclase-facies conditions, exemplified by the the Monte Sant'Agostino and the Monte Gavi mantle sections, respectively. We relate mantle domains (1) and (2) to a rifting-driven uplift in the late Triassic accommodated by large-scale shear zones consisting of anhydrous plagioclase mylonites. Hidas K., Borghini G., Tommasi A., Zanetti A. & Rampone E. 2021. Interplay between melt infiltration and deformation in the deep lithospheric mantle (External Liguride ophiolite, North Italy). Lithos 380-381, 105855

    Impact of Etna’s volcanic emission on major ions and trace elements composition of the atmospheric deposition

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    Mt. Etna, on the eastern coast of Sicily (Italy), is one of the most active volcanoes on the planet and it is widely recognized as a big source of volcanic gases (e.g., CO2 and SO2), halogens, and a lot of trace elements, to the atmosphere in the Mediterranean region. Especially during eruptive periods, Etna’s emissions can be dispersed over long distances and cover wide areas. A group of trace elements has been recently brought to attention for their possible environmental and human health impacts, the Technology-critical elements. The current knowledge about their geochemical cycles is still scarce, nevertheless, recent studies (Brugnone et al., 2020) evidenced a contribution from the volcanic activity for some of them (Te, Tl, and REE). In 2021, in the framework of the research project “Pianeta Dinamico”, by INGV, a network of 10 bulk collectors was implemented to collect, monthly, atmospheric deposition samples. Four of these collectors are located on the flanks of Mt. Etna, other two are in the urban area of Catania and three are in the industrial area of Priolo, all most of the time downwind of the main craters. The last one, close to Cesarò (Nebrodi Regional Park), represents the regional background. The research aims to produce a database on major ions and trace element compositions of the bulk deposition and here we report the values of the main physical-chemical parameters and the deposition fluxes of major ions and trace elements from the first year of research. The pH ranged from 3.1 to 7.7, with a mean value of 5.6, in samples from the Etna area, while it ranged between 5.2 and 7.6, with a mean value of 6.4, in samples from the other study areas. The EC showed values ranging from 5 to 1032 μS cm-1, with a mean value of 65 μS cm-1. The most abundant ions were Cl- and SO42- for anions, Na+ and Ca+ for cations, whose mean deposition fluxes, considering all sampling sites, were 16.6, 6.8, 8.4, and 6.0 mg m-2 d, respectively. The highest deposition fluxes of volcanic refractory elements, such as Al, Fe, and Ti, were measured in the Etna’s sites, with mean values of 948, 464, and 34.3 μg m-2 d-1, respectively, higher than those detected in the other sampling sites, further away from the volcanic source (26.2, 12.4, 0.5 μg m-2 d-1, respectively). The same trend was also observed for volatile elements of prevailing volcanic origin, such as Tl (0.49 μg m-2 d-1), Te (0.07 μg m-2 d-1), As (0.95 μg m-2 d-1), Se (1.92 μg m-2 d-1), and Cd (0.39 μg m-2 d-1). Our preliminary results show that, close to a volcanic area, volcanic emissions must be considered among the major contributors of ions and trace elements to the atmosphere. Their deposition may significantly impact the pedosphere, hydrosphere, and biosphere and directly or indirectly human health

    Impact of geogenic degassing on C-isotopic composition of dissolved carbon in karst systems of Greece

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    The Earth C-cycle is complex, where endogenic and exogenic sources are interconnected, operating in a multiple spatial and temporal scale (Lee et al., 2019). Non-volcanic CO2 degassing from active tectonic structures is one of the less defined components of this cycle (Frondini et al., 2019). Carbon mass-balance (Chiodini et al., 2000) is a useful tool to quantify the geogenic carbon output from regional karst hydrosystems. This approach has been demonstrated for central Italy and may be valid also for Greece, due to the similar geodynamic settings. Deep degassing in Greece has been ascertained mainly at hydrothermal and volcanic areas, but the impact of geogenic CO2 released by active tectonic areas has not yet been quantified. The main aim of this research is to investigate the possible deep degassing through the big karst aquifers of Greece. Since 2016, 156 karst springs were sampled along most of the Greek territory. To discriminate the sources of carbon, the analysis of the isotopic composition of carbon was carried out. δ13CTDIC values vary from -16.61 to -0.91‰ and can be subdivided into two groups characterized by (a) low δ13CTDIC, and (b) intermediate to high δ13CTDIC with a threshold value of -6.55‰. The composition of the first group can be related to the mixing of organic-derived CO2 and the dissolution of marine carbonates. Springs of the second group, mostly located close to Quaternary volcanic areas, are linked to possible carbon input from deep sources

    Earthquake Engineering

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    The book Earthquake Engineering - From Engineering Seismology to Optimal Seismic Design of Engineering Structures contains fifteen chapters written by researchers and experts in the fields of earthquake and structural engineering. This book provides the state-of-the-art on recent progress in the field of seimology, earthquake engineering and structural engineering. The book should be useful to graduate students, researchers and practicing structural engineers. It deals with seismicity, seismic hazard assessment and system oriented emergency response for abrupt earthquake disaster, the nature and the components of strong ground motions and several other interesting topics, such as dam-induced earthquakes, seismic stability of slopes and landslides. The book also tackles the dynamic response of underground pipes to blast loads, the optimal seismic design of RC multi-storey buildings, the finite-element analysis of cable-stayed bridges under strong ground motions and the acute psychiatric trauma intervention due to earthquakes

    African Handbook of Climate Change Adaptation

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    This open access book discusses current thinking and presents the main issues and challenges associated with climate change in Africa. It introduces evidences from studies and projects which show how climate change adaptation is being - and may continue to be successfully implemented in African countries. Thanks to its scope and wide range of themes surrounding climate change, the ambition is that this book will be a lead publication on the topic, which may be regularly updated and hence capture further works. Climate change is a major global challenge. However, some geographical regions are more severly affected than others. One of these regions is the African continent. Due to a combination of unfavourable socio-economic and meteorological conditions, African countries are particularly vulnerable to climate change and its impacts. The recently released IPCC special report "Global Warming of 1.5º C" outlines the fact that keeping global warming by the level of 1.5º C is possible, but also suggested that an increase by 2º C could lead to crises with crops (agriculture fed by rain could drop by 50% in some African countries by 2020) and livestock production, could damage water supplies and pose an additonal threat to coastal areas. The 5th Assessment Report produced by IPCC predicts that wheat may disappear from Africa by 2080, and that maize— a staple—will fall significantly in southern Africa. Also, arid and semi-arid lands are likely to increase by up to 8%, with severe ramifications for livelihoods, poverty eradication and meeting the SDGs. Pursuing appropriate adaptation strategies is thus vital, in order to address the current and future challenges posed by a changing climate. It is against this background that the "African Handbook of Climate Change Adaptation" is being published. It contains papers prepared by scholars, representatives from social movements, practitioners and members of governmental agencies, undertaking research and/or executing climate change projects in Africa, and working with communities across the African continent. Encompassing over 100 contribtions from across Africa, it is the most comprehensive publication on climate change adaptation in Africa ever produced

    Planet Earth 2011

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    The failure of the UN climate change summit in Copenhagen in December 2009 to effectively reach a global agreement on emission reduction targets, led many within the developing world to view this as a reversal of the Kyoto Protocol and an attempt by the developed nations to shirk out of their responsibility for climate change. The issue of global warming has been at the top of the political agenda for a number of years and has become even more pressing with the rapid industrialization taking place in China and India. This book looks at the effects of climate change throughout different regions of the world and discusses to what extent cleantech and environmental initiatives such as the destruction of fluorinated greenhouse gases, biofuels, and the role of plant breeding and biotechnology. The book concludes with an insight into the socio-religious impact that global warming has, citing Christianity and Islam

    Liaison White Rabbit dédiée au scanner de tomographie par émission de positrons LabPET II compatible à l'imagerie par résonance magnétique

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    La tomographie par émission de positrons (TEP) est une méthode d’imagerie médicale permettant de comprendre les bioprocessus à la base de la vie. Elle est parfois combinée à l’imagerie par résonance magnétique (IRM) afin d’ajouter un support structurel à l’information métabolique et ainsi faciliter le diagnostic. Cette combinaison permet, entre autres, de mieux localiser et comprendre les mécanismes d’évolution des démences, telle que la maladie d’Alzheimer dans le cas de l’imagerie cérébrale. La conception de circuits électroniques pouvant s’insérer à l’intérieur d’un scanner IRM implique toutefois plusieurs contraintes en raison des intenses variations de champs magnétiques nécessaires à cette méthode d’imagerie. En conséquence, le projet présenté vise à modifier les circuits d’acquisition dédiés à la TEP, en cours de développement au GRAMS, afin de les rendre compatibles à l’IRM. Cela implique, entre autres, de simplifier le mode de connexion des cartes, en passant un signal d’horloge, un signal de synchronisation et une connexion Ethernet Gigabit sur une seule fibre optique, par l’entremise du protocole White Rabbit. Un nouveau circuit d’acquisition a d’abord été conçu pour combiner l’électronique du LabPET II au protocole White Rabbit. Le noyau logiciel du protocole a ensuite été modifié pour synchroniser une horloge de 100 MHz nécessaire à l’électronique LabPET II, plutôt que l’horloge de 125 MHz utilisée de façon native dans le protocole. Un signal de synchronisation a aussi été régénéré à partir des informations temporelles fournies par le noyau White Rabbit. Finalement, un circuit d’interface a été conçu pour transférer les données entre le noyau White Rabbit et le processeur ARM localisé à l’intérieur du système sur puce Zynq. Les résultats obtenus en termes de précision temporelle dépassent largement les requis, même en présence de champs magnétiques générés en laboratoire. Une précision de 10,00 ps a été obtenue dans les meilleures conditions, alors qu’une précision de 28,73 ps a été obtenue dans le pire des scénarios testés. Peu importe le cas testé, les valeurs mesurées sont toutes négligeables par rapport aux autres sources d’instabilité temporelle du scanner. Un débit de données de 617 Mbit/s a été atteint entre le circuit testé et un ordinateur. Malgré quelques erreurs de communication lors des tests avec interférences, le débit moyen n’a pas été significativement affecté par les variations de champs magnétiques

    Contribuciones a la electrĂłnica de adquisiciĂłn y sincronismo del telescopio de neutrinos KM3NeT

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    Casi todo el conocimiento que se tiene sobre el Universo se ha obtenido mediante observaciones de ondas electromagnéticas, donde se engloban ondas de radio, infrarrojos, luz visible, luz ultravioleta, rayos X y rayos gamma. Sin embargo, además de los fotones, existen otros mensajeros cósmicos como los rayos cósmicos, los neutrinos o las recientemente descubiertas ondas gravitacionales, que pueden proporcionarnos conocimientos importantes para aumentar nuestra comprensión del Universo. Los rayos cósmicos bombardean nuestra atmósfera continuamente desde el espacio con energías de hasta 1020 eV. A pesar de que se han conseguido grandes avances para medir y entender su espectro de energía, han transcurrido más de 100 años desde su descubrimiento sin que se conozca con certeza su origen ni los mecanismos que consiguen acelerarlos a energías tan altas. No obstante, en la generación y aceleración de los rayos cósmicos se producen rayos gamma y neutrinos, los cuales, por su naturaleza, pueden tener un papel fundamental para revelar el origen y el mecanismo de aceleración de estas partículas. El neutrino tiene unas propiedades especiales que lo convierten en un mensajero cósmico único. Se trata de una partícula neutra, con apenas masa y que solo interacciona con la materia a través de la interacción débil. Esto le permite viajar enormes distancias sin que su trayectoria se vea alterada, así como atravesar objetos compactos y muy densos como el interior de las estrellas. Pero esas mismas propiedades hacen que su detección sea extremadamente difícil. Es por ello por lo que los detectores de neutrinos tienen que abarcar un volumen del orden de un km3 para poder detectarlos. Además, el principio de operación de los telescopios de neutrinos basado en la detección de fotones Cherenkov hace necesario que estén ubicados dentro de un medio transparente de grandes dimensiones como puede ser el agua del fondo de los océanos, lagos profundos o el hielo antártico. Los trabajos desarrollados en esta tesis doctoral se engloban dentro de la construcción de la infraestructura KM3NeT, una red de telescopios submarinos que estará ubicada en el fondo del mar Mediterráneo, y que una vez terminada, será el mayor telescopio de neutrinos construido hasta la fecha. Se describe la el diseño de la tarjeta electrónica principal del experimento KM3NeT, la denominada Central Logic Board donde se explica tanto el diseño como las funciones principales que dicha tarjeta desempeña. Sí mismo se describen las contribuciones aportadas a la implementación de la red de sincronismo de KM3NeT. El difícil emplazamiento del experimento, así como su topología, hacen que sea necesario utilizar un robusto protocolo de sincronismo que permita obtener la resolución angular deseada. También, en relación a la dificultad del emplazamiento del experimento, y la imposibilidad de realizar reparaciones en los módulos ópticos, la fiabilidad se convierte en un punto fundamental para garantizar la viabilidad de KM3NeT a largo plazo. Por ello, se expone de forma detallada los estudios de fiabilidad realizados a las principales tarjetas electrónicas que componen los módulos ópticos. Finalmente, se describe el firmware desarrollado para el sistema de adquisición, donde se muestra con detalle todos los componentes del sistema de adquisición, su verificación experimental en el laboratorio, así como los resultados obtenidos in situ con las primeras líneas instaladas en el fondo del mar que confirman dicha verificación
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