3,381 research outputs found
Geology and sedimentary facies of the Pliocene succession of the Baronia Mountains (Ariano Basin, southern Italy)
An up to 1500 m-thick clastic succession, the late Zanclean Baronia Synthem, has been analysed in detail in the Ariano wedge-top Basin (southern Apennine, Italy). In the Baronia Mountains the studied sediments are well exposed and laterally mappable due to young uplift and exhumation and rest unconformably on a complexly deformed pre-Pliocene substratum formed by Triassic to Miocene allochthonous units. The Baronia Synthem has been resolved into seven facies associations that are representative of distinct fluvial, deltaic, nearshore and offshore depositional environments and can be grouped into lowstand, transgressive, and highstand systems tracts. Using an integrated approach comprising original geological field mapping at 1:10,000 scale, conventional sedimentary facies analysis and a sequence stratigraphic approach, this paper provides a detailed description and interpretation of facies associations and new insights on the stratigraphic architecture and the geological history of this portion of the basin fill
Superficial and deep-seated gravity-driven deformation horizons within basinal succession: the case study of Maiolica Formation, Gargano Promontory, Southern Italy
Gravitational phenomena on the paleoslope of continental margins play a significant role both in redistribution
of sediment and formation of new structural features within sedimentary basins worldwide. Mass-transport
deposits (MTDs) represent important heterogeneities within the succession and occur on various scales (tens of
centimetres to hundreds of metres). Small- to medium-scale MTDs (up to tens of meters) act as layers of different petrophysical properties, whereas large-scale MTDs (tens to hundreds of meters) form both stratigraphic and structural discontinuities (faults, thrusts, erosional surfaces, dykes or injections) within the succession.
The Maiolica Formation, Early Cretaceous deep basinal succession cropping out in Gargano Promontory of
Southeast Italy is represented by undisturbed intervals of flat-lying thin-bedded, cherty micritic limestone
interstratified with intervals of lithologically similar, but structurally distorted beds. For this reason, the studied
outcrops provide a good opportunity to characterize the geometry and the internal deformation of small- and
medium-scale carbonate MTDs. At the outcrop scale, small- to medium-sized MTDs can be simply identified
as sheets of deformed strata alternated with packages of undeformed beds. However, several observed features such as folded stylolites with radially oriented peaks within some of these deformed packages and the presence of large vertical clastic-dyke-like bodies in the succession suggest that some of these deformed packages represent deep-seated basal gliding horizons of large-scale MTDs.
In this study, we present MTDs on two different scales that have a crucial influence on the evolution of slope
to basinal successions. Moreover, we define the features that distinguish superficial MTDs from the deep-seated
gravity-driven deformation horizons within basinal carbonates
Invariant methods for an ensemble-based sensitivity analysis of a passive containment cooling system of an AP1000 nuclear power plant
open4noSensitivity Analysis (SA) is performed to gain fundamental insights on a system behavior that is usually reproduced by a model and to identify the most relevant input variables whose variations affect the system model functional response. For the reliability analysis of passive safety systems of Nuclear Power Plants (NPPs), models are Best Estimate (BE) Thermal Hydraulic (TH) codes, that predict the system functional response in normal and accidental conditions and, in this paper, an ensemble of three alternative invariant SA methods is innovatively set up for a SA on the TH code input variables. The ensemble aggregates the input variables raking orders provided by Pearson correlation ratio, Delta method and Beta method. The capability of the ensemble is shown on a BE-TH code of the Passive Containment Cooling System (PCCS) of an Advanced Pressurized water reactor AP1000, during a Loss Of Coolant Accident (LOCA), whose output probability density function (pdf) is approximated by a Finite Mixture Model (FMM), on the basis of a limited number of simulations.Di Maio, Francesco; Nicola, Giancarlo; Borgonovo, Emanuele; Zio, EnricoDI MAIO, Francesco; Nicola, Giancarlo; Borgonovo, Emanuele; Zio, Enric
A statistical-based approach for determining the intensity of unrest phases at Stromboli volcano (Southern Italy) using one-step-ahead forecasts of displacement time series
A statistical-based approach for determining the intensity of unrest phases at Stromboli volcano (Southern Italy) using one-step-ahead forecasts of displacement time series
The evaluation of the intensity of unrest phases at active volcanoes is a crucial topic in volcano hazard studies. This is particularly troublesome in the case of persistently active volcanoes like Stromboli (Southern Italy), where intense eruptive summit activity (overflows, strong spattering, powerful explosions) has in some cases anticipated a flank eruption. In this context, a new approach for the analysis of displacement data is introduced. Daily displacements of the Stromboli crater terrace measured between January 1, 2010, and August 7, 2014, by a ground-based interferometric synthetic aperture radar system were compared, in retrospect, to displacement predictions provided by an autoregressive integrated moving average-based model. The methodology consisted in assessing when the actual displacements exceeded a fixed probability threshold for the forecasts (*95 %). Two sets of data were consequently produced: (1) series of residuals between actual displacements and model threshold (‘‘anomalies’’) and (2) series of normalized residuals between actual displacements and model threshold (‘‘normalized anomalies’’). This permitted to statistically identify and quantify the anomalous deformation at the crater terrace over the reference time interval of the analysis. Anomalies started to occur before each period of intense volcanic activity, highlighting the possibility to discern between background activity and unrest. Moreover, results indicated that the inflation of the crater terrace during the preparatory phase of the 2014 flank eruption was characterized by the greatest amount of anomalous deformation
Constraining the fraction of binary black holes formed in isolation and young star clusters with gravitational-wave data
Ten binary black-hole mergers have already been detected during the first two
observing runs of advanced LIGO and Virgo, and many more are expected to be
observed in the near future. This opens the possibility for gravitational-wave
astronomy to better constrain the properties of black hole binaries, not only
as single sources, but as a whole astrophysical population. In this paper, we
address the problem of using gravitational-wave measurements to estimate the
proportion of merging black holes produced either via isolated binaries or
binaries evolving in young star clusters. To this end, we use a Bayesian
hierarchical modeling approach applied to catalogs of merging binary black
holes generated using state-of-the-art population synthesis and N-body codes.
In particular, we show that, although current advanced LIGO/Virgo observations
only mildly constrain the mixing fraction between the two
formation channels, we expect to narrow down the fractional errors on to
after a few hundreds of detections.Comment: 17 pages, 4 figure
Guidelines on the use of inverse velocity method as a tool for setting alarm thresholds and forecasting landslides and structure collapses
Passive Sampling of Organic Contaminants as a Novel Approach to Monitor Seawater Quality in Aquarium Ocean Tanks
The determination of trace pollutants in seawater is challenging, and sampling is a crucial step in the entire analytical process. Passive samplers combine in situ sampling and preconcentration, thus limiting the tedious treatment steps of the conventional sampling methods. Their use to monitor water quality in confined marine environment could bring several advantages. In this work, the presence of organic contaminants at trace and ultra-trace levels was assessed in the Genoa Aquarium supply-and-treated water using Polar Organic Integrative Samplers (POCIS). Both untargeted gas chromatography-mass spectrometry and targeted liquid chromatography-tandem mass spectrometry were employed. The untargeted approach showed the presence of hydrocarbons, diphenyl sulfone and 2,4-di-tert-butyl-phenol. Only hydrocarbons were detected in all the samples. Nineteen emerging contaminants, belonging to different classes (pharmaceuticals, UV-filters, hormones and perfluorinated compounds), were selected for the target analysis. Thirteen analytes were detected, mainly in supply water, even though the majority of them were below the quantitation limit. It is worthy to note that two of the detected UV-filters had never been reported in seawater using the POCIS samplers. The comparison of the analytes detected in supply and treated water indicated a good performance of the Aquarium water treatment system in the abatement of seawater contaminants
Guidelines on the use of inverse velocity method as a tool for setting alarm thresholds and forecasting landslides and structure collapses
Predicting the time of failure is a topic of major concern in the field of geological risk management. Several approaches, based on the analysis of displacement monitoring data, have been proposed in recent years to deal with the issue. Among these, the inverse velocity method surely demonstrated its effectiveness in anticipating the time of collapse of rock slopes displaying accelerating trends of deformation rate. However, inferring suitable linear trend lines and deducing reliable failure predictions from inverse velocity plots are processes that may be hampered by the noise present in the measurements; data smoothing is therefore a very important phase of inverse velocity analyses. In this study, different filters are tested on velocity time series from four case studies of geomechanical failure in order to improve, in retrospect, the reliability of failure predictions: Specifically, three major landslides and the collapse of an historical city wall in Italy have been examined. The effects of noise on the interpretation of inverse velocity graphs are also assessed. General guidelines to conveniently perform data smoothing, in relation to the specific characteristics of the acceleration phase, are deduced. Finally, with the aim of improving the practical use of the method and supporting the definition of emergency response plans, some standard procedures to automatically setup failure alarm levels are proposed. The thresholds which separate the alarm levels would be established without needing a long period of neither reference historical data nor calibration on past failure events
Skeletal muscle myopenia in mice model of bile duct ligation and carbon tetrachloride-induced liver cirrhosis
Skeletal muscle myopathy is universal in cirrhotic patients, however, little is known about the main mechanisms involved. The study aims to investigate skeletal muscle morphological, histological, and functional modifications in experimental models of cirrhosis and the principal molecular pathways responsible for skeletal muscle myopathy. Cirrhosis was induced by bile duct ligation (BDL) and carbon tetrachloride (CCl4) administration in mice. Control animals (CTR) underwent bile duct exposure or vehicle administration only. At sacrifice, peripheral muscles were dissected and weighed. Contractile properties of extensor digitorum longus (EDL) were studied in vitro. Muscle samples were used for histological and molecular analysis. Quadriceps muscle histology revealed a significant reduction in cross-sectional area of muscle and muscle fibers in cirrhotic mice with respect to CTR. Kinetic properties of EDL in both BDL and CCl4 were reduced with respect to CTR; BDL mice also showed a reduction in muscle force and a decrease in the resistance to fatigue. Increase in myostatin expression associated with a decrease in AKT-mTOR expressions was observed in BDL mice, together with an increase in LC3 protein levels. Upregulation of the proinflammatory citochines TNF-a and IL6 and an increased expression of NF-kB and MuRF-1 were observed in CCl4 mice. In conclusion, skeletal muscle myopenia was present in experimental models of BDL and CCl4-induced cirrhosis. Moreover, reduction in protein synthesis and activation of protein degradation were the main mechanisms responsible for myopenia in BDL mice, while activation of ubiquitin-pathway through inflammatory cytokines seems to be the main potential mechanism involved in CCl4 mice
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