Role of shellfish hatchery as a reservoir of antimicrobial resistant bacteria

The main aim of this study was to determine the occurrence of resistant bacteria in florfenicol-treated and untreated scallop larval cultures from a commercial hatchery and to characterize some selected florfenicol-resistant strains. Larval cultures from untreated and treated rearing tanks exhibited percentages of copiotrophic bacteria resistant to florfenicol ranging from 0.03% to 10.67% and 0.49–18.34%, respectively, whereas florfenicol resistance among oligotrophic bacteria varied from 1.44% to 35.50% and 3.62–95.71%, from untreated and treated larvae, respectively. Florfenicol resistant microbiota from reared scallop larvae mainly belonged to the Pseudomonas and Pseudoalteromonas genus and were mainly resistant to florfenicol, chloramphenicol, streptomycin and co-trimoxazole. This is the first study reporting antimicrobial resistant bacteria associated to a shellfish hatchery and the results suggest that a continuous surveillance of antimicrobial resistance even in absence of antibacterial therapy is urgently required to evaluate potential undesirable consequences on the surrounding environments.     

Focus-of-attention techniques in the automatic interpretation of seismograms

The focus-of-attention techniques implemented in SNA2, a knowledge-based system for seismogram interpretation, are presented. They consist of data compression of the input digital records, scanning of the compressed traces to detect candidate seismograms and extraction of seismogram features. A criterion is given to rate the clarity of seismograms; the clarity defines the order in which the system will consider them to build up the interpretation. The proposed techniques are simple and fast; they allow quick rejection of noise and focussing the attention of the system on the portions of traces containing relevant information.     

The Neapolitan Yellow Tuff — A large volume multiphase eruption from Campi Flegrei,Southern Italy

the Neapolitan Yellow Tuff (NYT) (12 ka BP) is considered to be the product of a single eruption. Two different members (A and B) have been identified and can be correlated around the whole of Campi Flegrei. Member A is made up of at least 6 fall units including both ash and lapilli horizons. The basal stratified ash unit (A1) is interpreted to be a phreatoplinian fall deposit, since it shows a widespread dispersal (>1000 km²) and a constant thickness over considerable topography. The absence of many lapilli fall units in proximal and medial areas testifies to the erosive power of the intervening pyroclastic surges. The overlying member B was formed by many pyroclastic flows, radially distributed around Campi Flegrei, that varied widely in their eruptive and emplacement mechanisms. In some of the most proximal exposures coarse scoria and lithic-rich deposits, sometimes welded, have been identified at the base of member B. Isopach and isopleth maps of fall-units, combined with the distribution of the coarse proximal facies, indicate that the eruptive vent was located in the NE area of Campi Flegrei. It is considered that the NYT eruption produced collapse of a caldera approximately 10 km diameter within Campi Flegrei. The caldera rim, located by geological and borehole evidence, is now largely buried by the products of more recent eruptions. Initiation of caldera collapse may have been contemporaneous with the start of the second phase (member B). It is suggested that there was a single vent throughout the eruption rather than the development of multiple or ring vents. Chemical data indicate that different levels of a zoned trachyte-phonolite magma chamber were tapped during the eruption. The minimum volume of the NYT is calculated to be about 50 km³ (DRE), of which 35 km³ (70%) occurs within the caldera.     

Instrumental seismological data since 1900 for northeastern Italy

Statistical analyses on a catalogue of instrumental data for earthquakes in northeastern Italy since 1900 are presented. The different types of magnitude, which are the main parameters under study, have been evaluated so as to be as homogeneous as possible. Comparisons of the different magnitude values show linear dependence, at least in the medium magnitude range represented by the available data set. Correlations between the magnitude most significant for this region and chosen macroseismic data indicate a methodology for assessing the macroseismic magnitude of historical earthquakes which seems to be stable.     

Large-scale stratigraphic architecture and sequence analysis of an early Pleistocene submarine canyon fill,Monte Ascensione succession (Peri-Adriatic basin,eastern central Italy)

The Monte Ascensione succession (c. 2.65–2.1 Ma) is a well-exposed example of an exhumed submarine canyon fill embedded within slope hemipelagic mudstones. This gorge represented a long-lasting pathway for sediment transport and deposition and during the Gelasian delivered Apennine-derived clastic sediment to the adjacent Peri-Adriatic basin. A total of six principal lithofacies types, representing both canyon-confining hemipelagic deposits and canyon-filling turbidity current and mass-transport deposits, can be delineated in the studied sedimentary succession. The canyon-fill deposits display a marked cyclic character and the component lithofacies succeed one another to form at least fifteen fining-upward stratal units, which are interpreted to represent high-frequency, unconformity-bounded depositional sequences. Variability in the vertical repetition of constituent lithofacies allows the identification of three basic styles of sequence architecture that can be interpreted in terms of differing positions along a conceptual down-canyon depositional profile. An integrated chronology, based on biostratigraphic data and on palaeomagnetic polarity measurements, strongly supports a one-to-one correlation between the sequence-bounding surfaces and oxygen isotope stages G2–78, suggesting that the most feasible sequence-engendering mechanism is that of orbitally dictated glacio-eustatic changes in sea level, which regulated timing of sediment storage on the shelf and its redistribution beyond the shelf edge. One of the most significant aspects of this study is the demonstration that processes occurring within upper slope canyons can be expected to be strongly influenced by variations in sea level; that is, the erosional and depositional features evident in these deposits can be strongly controlled by allocyclic processes rather than autocyclic or random processes.     

A component approach for the hysteretic behaviour of connections in cross‐laminated wooden structures

In this paper, a numerical model to estimate the dissipative capacity and describe the cyclic response of cross‐laminated (X‐lam) timber buildings is presented. The connections between panels and to the foundation (metal hold‐downs and angle brackets, and screwed connectors) are modelled with nonlinear hysteretic multispring elements taking into account the strength interaction between different degrees of freedom according to a predefined domain. The timber components (solid X‐lam floors and wall panels) are modelled using elastic shell elements. By calibration on experimental cyclic tests carried out on each degree of freedom, important features of timber connection behaviour such as post‐peak strength, pinching and stiffness degradation can all be considered. In addition, the effect of friction at the interface between panels and with foundation can be taken into account. These springs have been implemented as external subroutines in a widespread software package such as Abaqus. By comparison with the experimental results of cyclic tests carried out on single X‐lam walls, coupled X‐lam walls and a single‐storey X‐lam building, the accuracy of the proposed model is demonstrated. Copyright © 2013 John Wiley & Sons, Ltd.     

Effects of the invasive plant Lupinus polyphyllus on vertical accretion of fine sediment and nutrient availability in bars of the gravel-bed Paloma river

Floodplain vegetation is fundamental in fluvial systems, controlling river corridor geomorphology and ecology through a series of hydraulic, sedimentological, and biological processes. Changes caused by introduced plant species can thus result in shifts in river regime, succession trajectories and nutrient availability, affecting native biodiversity. The exotic bigleaf or marsh lupine Lupinus polyphyllus, introduced in Patagonia in the last decades, is aggressively invading fluvial corridors. It fills unoccupied ecological niches in southern Chilean rivers, due to its capacity for nitrogen fixation, its perennial habit, and high shoot density and leaf surface area.We investigated the effects of L. polyphyllus on vertical accretion of fine sediment, and soil carbon and nitrogen content, on gravel bars of the Paloma river, Chilean Patagonia, where lupine is believed to have been introduced in 1994. We sampled plot pairs with and without lupine, with each pair located at the same elevation above river stage, and plots distributed over the reach scale. We measured the thickness of the fine soil horizon, grain size distribution, and soil carbon and nitrogen content. We also compared aerial photographs to evaluate changes in spatial coverage of lupine along the study reach.Presence of lupine was strongly correlated with a thicker layer of finer sediment, in turn characterized by higher organic carbon, carbon to nitrogen ratio, and inorganic carbon content. Contrary to our expectations, we did not find any significant differences in total nitrogen. Aerial photographs did not reveal important differences in coverage between 2007 and 2010, but plant density appears to have increased between the two dates, and invaded gravel bars also appear to be more stable. Lupine dominance of otherwise sparsely vegetated gravel bars in Patagonian rivers appears to have greatest consequences on bar physical structure (increased rates of accretion of fines) and secondary repercussions on soil quality (increase in recalcitrant organic matter), with potential transient effects on nutrient availability (possible increased soil metabolism, followed by carbon mineralization and loss of lupine nitrogen subsidy).     

Post-earthquake estimates of different ground motion intensity measures for the 2012 Emilia earthquake

Estimates of the earthquake ground motion intensity over a geographical area have multiple uses, that is, emergency management, civil protection and seismic fragility assessment. In particular, with reference to fragility assessment, it is of interest to have estimates of the values of different ground-motion intensity measures in order to correlate them with the observed damage. To this purpose, the present paper uses a procedure recently proposed in the literature to estimate the ground-motion intensity for the 2012 Emilia mainshocks, considering different ground motion intensity measures and directionality effects. Ground motion prediction equations based on different site effect models, and spatial correlation models are calibrated for the Emilia earthquakes. The paper discusses the accuracy of the shakemaps obtained using the different soil effect models considered and presents the obtained shakemaps as supplementary material. The procedure presented in the paper is aimed at providing ground motion intensity values for seismic fragility assessment and is not intended as a tool to estimate shakemaps for rapid emergency assessment.