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Lentini, Valentina
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Lentini, Valentina
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- PublicationRestrictedDynamic characterization of fine-grained soils in Central Italy by laboratory testing(2020)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; The investigation of soil response to dynamic loads is necessary to predict site-specific seismic hazard. This paper presents the results of cyclic and dynamic laboratory tests carried out after the 2016–2017 Central Italy Earthquake sequence, within the framework of the seismic microzonation studies of the most damaged municipalities in the area. The database consists of 79 samples investigated by means of dynamic resonant column tests, cyclic torsional shear tests or cyclic direct simple shear tests. Results are firstly analysed in terms of field and laboratory values of small-strain shear wave velocity, highlighting the influence of the sample disturbance and of the mean effective consolidation pressure. The cyclic threshold shear strains as a function of plasticity index are then compared with findings from the published literature and the outliers are analysed. Subsequently, the dynamic soil behaviour is investigated with reference to the small-strain damping ratio. Differences between results from different tests are analysed in the light of the loading frequencies. Finally, the database is used to develop a predictive model for soil nonlinear curves according to plasticity index, mean effective confining stress, and loading frequency. The model represents a useful tool to predict the nonlinear stress–strain behaviour of Central Italy soils, necessary to perform site-specific ground response analyses.70 2 - PublicationRestrictedBacterial and archaeal populations at two shallow hydrothermal vents off Panarea Island (Eolian Islands, Italy)(2009-01)
; ; ; ; ; ; ;Maugeri, T.; Dipartimento di Biologia Animale ed Ecologia Marina, Universita` di Messina ;Lentini, V.; Dipartimento di Biologia Animale ed Ecologia Marina, Universita` di Messina ;Gugliandolo, C.; Dipartimento di Biologia Animale ed Ecologia Marina, Universita` di Messina ;Italiano, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Cousin, S.; Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, ;Stackebrandt, E.; ; ; ; ; The aim of this study was to investigate the microbial community thriving at two shallow hydrothermal vents off Panarea Island (Italy). Physico-chemical characteristics of thermal waters were examined in order to establish the effect of the vents on biodiversity of both Bacteria and Archaea. Water and adjacent sediment samples were collected at different times from two vents, characterised by different depth and temperature, and analysed to evaluate total microbial abundances, sulphuroxidising and thermophilic aerobic bacteria. Total microbial abundances were on average of the order of 105 cells ml-1, expressed as picoplanktonic size fraction. Picophytoplanktonic cells accounted for 0.77–3.83% of the total picoplanktonic cells. The contribution of bacterial and archaeal taxa to prokaryotic community diversity was investigated by PCR–DGGE fingerprinting method. The number of bands derived from bacterial DNA was highest in the DGGE profiles of water sample from the warmest and deepest site (site 2). In contrast, archaeal richness was highest in the water of the coldest and shallowest site (site 1). Sulphur-oxidising bacteria were detected by both culture- dependent and -independent methods. The primary production at the shallow hydrothermal system of Panarea is supported by a complex microbial community composed by phototrophs and chemolithotrophs.390 28 - PublicationRestrictedChanges in prokaryotic community composition accompanying a pronounced temperature shift of a shallow marine thermal brine pool (Panarea Island, Italy)(2015-01)
; ; ; ; ; ; ;Gugliandolo, C.; Department of Biological and Environmental Sciences, Research Centre for Extreme Environments and Extremophiles, University of Messina, ;Lentini, V.; Department of Biological and Environmental Sciences, Research Centre for Extreme Environments and Extremophiles, University of Messina, ;Bunk, B.; Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen, ;Overmann, J.; Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen ;Italiano, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Maugeri, T.; Department of Biological and Environmental Sciences, Research Centre for Extreme Environments and Extremophiles, University of Messina,; ; ; ; ; Hot Lake is a recently described thermal brine pool off Panarea Island (Eolian Islands, Italy) where emitted fluids are highly saline and rich in CO2 and H2S. The prokaryotic community composition in surface sediment samples was analyzed by high-throughput Illumina sequencing targeting the V3 region of the 16S rRNA at two time points that differed mainly with respect to temperature conditions, high-temperature (94 °C, HT09) and low-temperature (28.5 °C, LT10). Bacterial richness and diversity were greater than those of Archaea under both temperature conditions. In contrast to Bacteria, diversity and evenness of Archaea greatly increased at LT10. While the phylogenetic analysis indicated the presence of members mostly affiliated with the same taxonomic groups, their relative abundances differed from HT09 to LT10, resulting in different bacterial and archaeal assemblages. Both HT09 and LT10 were dominated by members of the Epsilonproteobacteria. Within this subphylum, bacteria of the genus Sulfurimonas were most frequently detected at HT09, while Arcobacter prevailed at LT10. The abundance of other dominant taxonomic groups (≥1 % of Illumina reads) also correlated with temperature conditions. Members assigned to hyperthermophilic Euryarchaeota (Thermococci) or to thermophilic (Caldiserica) and thermoresistant (Firmicutes) bacterial taxa were dominant at HT09, while those related to non-thermophilic Bacteroidetes, Fusobacteria and Actinobacteria were dominant at LT10. Several, probably photosynthetic, members of the Alphaproteobacteria, Chlorobi, Cyanobacteria and Chloroflexi were recovered under both temperature conditions. The co-occurrence of photosynthetic and chemolithotrophic microorganisms represents a unique feature of shallow vents such as Hot Lake260 63