92 research outputs found

    Spectral analysis of ground thermal image temperatures: what we are learning at Solfatara volcano (Italy)

    Get PDF
    Abstract. The Solfatara volcano in the Campi Flegrei caldera (Italy), is monitored by different, permanent ground networks handled by INGV (Istituto Nazionale di Geofisica e Vulcanologia), including thermal infrared cameras (TIRNet). The TIRNet network is composed by five stations equipped with FLIR A645SC or A655SC thermal cameras acquiring at nightime infrared scenes of portions of the Solfatara area characterized by significant thermal anomalies. The dataset processed in this work consists of daily maximum temperatures time-series from 25 April 2014 to 31 May 2019, acquired by three TIRNet stations (SF1 and SF2 inside Solfatara crater, and PIS near Pisciarelli boiling mud pool), and also consists of atmospheric pressure and air temperature time-series. Data pre-processing was carried out in order to remove the seasonal components and the influence of the Earth tides to the selected time-series. By using the STL algorithm (Seasonal Decomposition of Time Series by Loess), the time-series were decomposed into three components (seasonal, trend and remainder) to find seasonality and remove it. Then, a harmonic analysis was performed on the de-seasonalized signals in order to identify and remove the long-period tidal constituents (mainly fortnightly and monthly). Finally, Power Spectral Density was calculated by FFT Matlab algorithm, after applying an acausal Butterworth filter, focusing on the [15–120] d band, to check if characteristic periodicities exist for each site. The reliability and significance of the spectral peaks were proved by statistical and empirical methods. We found that most of the residual periodicities are ascribable to ambient factors, while 18.16 d for Pisciarelli site and 88.71 d for Solfatara have a possible endogenous origin

    The Long-Period seismicity before and during the volcanic crises: examples from two case studies

    Get PDF
    The Long-Period (LP) seismicity is common at active volcanoes and is usually modeled as due to pressurized magmatic fluids flowing through rock cavities. These signals are sensitive to the thermodynamic conditions of the magma-gas mixture in the shallow plumbing system and can thus be adopted as “detectors” of an impelling eruption. We found that at Stromboli (Italy) before and/or during recent volcanic crises the LP events can occur in swarms, which show different statistics, higher energy and shallower location than the stationary LP activity. We imputed the LP swarms to a quick depressurization (|ΔP|≥105 Pa) of the shallowest (<0.8 km) part of the conduit. At Shishaldin (Alaska) the 2004 eruption is anticipated by a migration towards the surface of the LP source, which moves from ~8 km to ≾5 km below the crater rim. By simple assumptions, we modeled this source change as produced by an increase of the confining pressure within the plumbing system of ~5x107 Pa, possibly induced by an upward migration of ~108-1010 kg of magma

    A long-lasting quiescence phase of the eruptive variable V1118 Ori

    Get PDF
    V1118 Ori is an eruptive variable belonging to the EXor class of Pre-Main Sequence stars whose episodic outbursts are attributed to disk accretion events. Since 2006, V1118 Ori is in the longest quiescence stage ever observed between two subsequent outbursts of its recent history. We present near-infrared photometry of V1118 Ori carried out during the last eight years, along with a complete spectroscopic coverage from 0.35 to 2.5 um. A longterm sampling of V1118 Ori in quiescence has never been done, hence we can benefit from the current circumstance to determine the lowest values (i.e. the zeroes) of the parameters to be used as a reference for evaluating the physical changes typical of more active phases. A quiescence mass accretion rate between 1--3 ×\times 109^{-9} M_{\sun} yr1^{-1} can be derived and the difference with previous determinations is discussed. From line emission and IR colors analysis a visual extinction of 1-2 mag is consistently derived, confirming that V1118 Ori (at least in quiescence) is a low-extinction T Tauri star with a bolometric luminosity of about 2.1 L_{\sun}. An anti-correlation exists between the equivalent width of the emission lines and the underlying continuum. We searched the literature for evaluating whether or not such a behaviour is a common feature of the whole class. The anti-correlation is clearly recognizable for all the available EXors in the optical range (Hβ\beta and Hα\alpha lines), while it is not as much evident in the infrared (Paβ\beta and Brγ\gamma lines). The observed anti-correlation supports the accretion-driven mechanism as the most likely to account for continuum variations.Comment: 6 figures, 5 tables, accepted on Ap

    Molecular Sensing by Nanoporous Crystalline Polymers

    Get PDF
    Chemical sensors are generally based on the integration of suitable sensitive layers and transducing mechanisms. Although inorganic porous materials can be effective, there is significant interest in the use of polymeric materials because of their easy fabrication process, lower costs and mechanical flexibility. However, porous polymeric absorbents are generally amorphous and hence present poor molecular selectivity and undesired changes of mechanical properties as a consequence of large analyte uptake. In this contribution the structure, properties and some possible applications of sensing polymeric films based on nanoporous crystalline phases, which exhibit all identical nanopores, will be reviewed. The main advantages of crystalline nanoporous polymeric materials with respect to their amorphous counterparts are, besides a higher selectivity, the ability to maintain their physical state as well as geometry, even after large guest uptake (up to 10–15 wt%), and the possibility to control guest diffusivity by controlling the orientation of the host polymeric crystalline phase. The final section of the review also describes the ability of suitable polymeric films to act as chirality sensors, i.e., to sense and memorize the presence of non-racemic volatile organic compounds

    Array and spectral ratio techniques applied to seismic noise to investigate the Campi Flegrei (Italy) subsoil structure at different scales

    Get PDF
    Abstract. The purpose of this work is to study the subsoil structure of the Campi Flegrei area using both spectral ratios and array techniques applied to seismic noise. We have estimated the dispersion curves of Rayleigh waves by applying the Frequency–Wavenumber (f–k hereinafter) and Modified Spatial Autocorrelation (MSPAC) techniques to the seismic noise recorded by the underground short period seismic Array "ARF", by the broadband stations of the UNREST experiment and by the broadband stations of the seismic monitoring network of INGV – Osservatorio Vesuviano. We have performed the inversion of a dispersion curve (obtained averaging the f–k and MSPAC dispersion curves of seismic noise and single phase velocity values of coherent transient signals) jointly with the H∕V spectral ratio of the broadband station CELG, to obtain a shear wave velocity model up to 2000 m depth. The best-fit model obtained is in a good agreement with the stratigraphic information available in the area coming from shallow boreholes and deep wells drilled for geothermal exploration. In active volcanic areas, such as Campi Flegrei, the definition of the velocity model is a crucial issue to characterize the physical parameters of the medium. Generally, a high quality characterization of the medium properties helps to separate the contributions of the volcanic source, path and site in the geophysical observables. Therefore, monitoring possible variations in time of such properties in general can help to recognize anomalies due to the volcano dynamics, i.e. fluid migration connected to the volcanic activity

    Experimental study for evaluation of a suitable ground displacement monitoring system: Pilot hole Campi Flegrei Deep Drilling Project case

    Get PDF
    The paper presents an experimental study carried out in 2012 during the drilling activity for a pilot hole performed in the framework of the Campi Flegrei Deep Drilling Project. A monitoring network has been installed to test and choose a suitable ground deformation system for the subsequent deep drilling of about 3.5 km in the Campi Flegrei Caldera (Italy). We describe the seismic network installed to characterize the structure of the pilot hole area and the ground deformation monitoring system chosen for the small drilling area. Data analysis and results obtained indicate that Total Station is a suitable tool for this case.Published4V. Dinamica dei processi pre-eruttiviN/A or not JC

    Effectiveness and safety of secukinumab in Italian patients with psoriasis: an 84 week, multicenter, retrospective real-world study

    Get PDF
    Background: Long term data on the real-life use of secukinumab are scant. The aim of this study was to investigate the real-life effectiveness, safety and treatment persistence of secukinumab in patients with moderate-to-severe psoriasis. Research design and methods: This 84-week, multicenter (n = 7) retrospective study analyzed data from patients who initiated and received at least 6 months of secukinumab treatment between June 2016 and June 2018 in the Campania region of Italy. Patient demographic and treatment characteristics, duration of treatment and reasons for discontinuation as well as Psoriasis Area and Severity Index (PASI), Body Surface Area (BSA), and Dermatology Life Quality Index (DLQI) scores were assessed. Results: 324 patients (63% male, mean age 50.2 years) were enrolled and received a mean 11.7 months of secukinumab treatment. Overall, 9.5% discontinued secukinumab, including 5.2% who discontinued due to secondary inefficacy and 1.8% due to adverse events. PASI, BSA and DLQI scores were significantly improved from baseline at every follow-up visit (p < 0.001) and mean PASI decreased from 15.3 ± 6.3 at baseline to 0.5 ± 1.0 at week 84. Secukinumab had comparable effectiveness in biologic naïve and non-naïve patients. Conclusions: This study confirmed the effectiveness and safety of secukinumab in real-world patients with psoriasis

    Preliminary analysis of site effects in the Ischia island: new insights from md 4.0 earthquake of 21 august 2017 and seismic noise data

    Get PDF
    On August 21, 2017, at 18:57 UTC, an earthquake of MD 4.0 occurred in Casamicciola, district of Ischia island. The damage caused by the earthquake was massive, with two victims and several buildings collapsed, and circumscribed to the areas of uptown Casamicciola, particularly in the Piazza Maio-La Rita area, and in a small area, called Fango, in Lacco Ameno. Medium and minor damages occurred in Piazza Bagni, in the area around the town hall of Casamicciola and in the Sentinella area. Even assuming the poor quality constructions and/or not in compliance with the anti-seismic regulations, such a level of damage has induced the scientific community to analyse the effects of local site amplifications, that usually are not negligible in volcanic areas. As a matter of fact the seismic station IOCA, located very close to the high damage areas, recorded a peak ground acceleration (PGA) of 2.6 m/s2. This paper is aimed to study the possible site amplification in the areas heavily affected by the August 21 earthquake in order to better understand the causes of these macroseismic effects and high damage levels already observed in the past.PublishedCentro Congressi della Stazione Marittima, Trieste, Italy6V. Pericolosità vulcanica e contributi alla stima del rischi

    The Borehole Experiment: Investigation of Cortical Structures Through 3D Array Techniques

    Get PDF
    Over the last few years it is growing the need to monitor the volcanic activity with modern technology in order to mitigate volcanic hazard through the detection of any possible precursor phenomena. The use of high performance seismic stations, such as borehole instruments, may increase the signal to noise ratio (SNR), improving the capability to detect very small signals. Over the past 40 years much attention has been given to the use of seismic arrays to measure the slowness vector of coherent signals. The main advantage of seismic arrays consists in their ability to detect weak or emergent signals, and to allow for an effective noise reduction through multichannel waveform stacking. A reliable prediction of the ray-path back-propagated from the recording site to the source is strongly limited by the poor knowledge of the local shallow velocity structure. Usually in volcanic environments the propagation of seismic signals through the shallow layers is strongly affected by lateral heterogeneity, attenuation, scattering, and interaction with the free surface. Driven by these motivations, on May 2014, in collaboration with the colleagues of Osservatorio Vesuviano (INGV), we deployed a 3D seismic array in the area where the borehole seismic station called Pozzo Pitarrone is installed at a depth of about 130 meters. This will improve our knowledge about: • the structure of the top layer and its relationship with geology; • analysis of the signal to noise ratio (SNR) of volcanic signals as a function of frequency; • study of seismic ray-path deformation caused by the interaction of the seismic waves with the free surface; • evaluation of the attenuation of the seismic signals correlated with the volcanic activity. The results of these analyses will improve the general knowledge of wave propagation in the shallow layers and will give a new contribution to the seismic monitoring of Etna volcano.PublishedNicolosi (Catania), Italy1T. Struttura della Terr

    May-Hegglin Anomaly, Sebastian Syndrome, Fechtner Syndrome, and Epstein Syndrome Are not Distinct Entities but Represent a Variable Expression of a Single Illness

    Get PDF
    May-Hegglin anomaly, Sebastian syndrome, Fechtner syndrome, and Epstein syndrome are autosomal dominant macrothrombocytopenias distinguished by different combinations of clinical and laboratory signs, such as sensorineural hearing loss, cataract, nephritis, and polymorphonuclear Döhle-like bodies. Mutations in the MYH9 gene encoding for the nonmuscle myosin heavy chain IIA (NMMHC-IIA) have been identified in all these syndromes. To understand the role of the MYH9 mutations, we report the molecular defects in 12 new cases, which together with our previous works represent a cohort of 19 families. Since no genotype-phenotype correlation was established, we performed an accurate clinical and biochemical re-evaluation of patients. In addition to macrothrombocytopenia, an abnormal distribution of NMMHC-IIA within leukocytes was observed in all individuals, including those without Döhle-like bodies. Selective, high-tone hearing deficiency and cataract was diagnosed in 83% and 23%, respectively, of patients initially referred as having May-Hegglin anomaly or Sebastian syndrome. Kidney abnormalities, such as hematuria and proteinuria, affected not only patients referred as Fechtner syndrome and Epstein syndrome but also those referred as May-Hegglin anomaly and Sebastian syndrome. These findings allowed us to conclude that May-Hegglin anomaly, Sebastian syndrome, Fechtner syndrome, and Epstein syndrome are not distinct entities but rather a single disorder with a continuous clinical spectrum varying from mild macrothrombocytopenia with leukocyte inclusions to a severe form complicated by hearing loss, cataracts, and renal failure. For this new nosologic entity, we propose the term "MHY9-related disease," which better interprets the recent knowledge in this field and identifies all patients at risk of developing renal, hearing, or visual defects
    corecore