Uncertainties in lava flow hazard maps derived from numerical simulations: the case study of Mount Etna

The procedure for the derivation of a hazard map for lava flows at Mount Etna through lava flow simulations is critically reviewed. The DOWNFLOW code is then used to explore the sensitivity of the hazard map with respect to input settings. Three parameters are varied within ranges close to values recently applied to derive similar hazard maps: (i) the spacing between computational vents; (ii) the spatial probability density function (PDF) for future vent opening; and (iii) the expected length of future lava flows. The effect of increasing the spacing between computational vents tends to be compensated at the lower elevations, and a vent spacing smaller than about 500 m warrants an overall difference with respect to a reference map which is smaller than 6–8%. A random subsampling of the elements used to obtain the input vent opening PDF (−20%, −40% and −60%) originates significant but drastically smaller differences in the obtained map with respect to the reference one (~10%, ~12.5% and ~17% respectively, on average). In contrast, our results show that changes in the expected flow length originate, by far, the highest changes in the obtained hazard map, with overall differences ranging between ~20% and ~65%, and between ~30% and ~95% if computed only over inhabited areas. The simulations collected are further processed to derive maps of the confluence/diffluence index,which quantifies the error introduced, locally, when the position of the vent is misplaced by a given distance

A Microscopic Information System (MIS) for petrographic analysis

The database and visualization facilities of Geographic Information System (GIS) software are employed to support the analysis of rock texture from thin section by image processing. A Microscopic Information System (MIS) is hence obtained. The method is applied to transmitted light images of 137 samples obtained from 8 granitoid rocks. A slide scanner and a mount for crossed polarization are used to acquire the input images. For each thin section 5 collimated RGB images are scanned: 4 under different directions of crossed polarization and 1 without polarization. A grain segmentation procedure, based on two region growing functions is applied. The output is converted to vector format and refined using editing tools in the MIS environment, which enables a straightforward match between the input imagery and the final vectorized texture. GIS software provides optimal management of the MIS database, allowing the cumulative measurement of more than 87 000 grains

Capturing full resolution perspective and stereo views of large DEMs

A custom software to capture still views of images draped on digital surfaces is presented. It is called ViCam (for virtual camera). Unlike off the shelf software packages, our system is completely controlled by the user, allowing the visualization of a scene from an arbitrary viewpoint with an arbitrary (virtual) optic geometry (i.e. field of view angle). This software can work in loop over very large tiled datasets handled by a Geographic Information System (GIS) package, providing in output global views of the entire input area as single and seamless image layers at any desired resolution. Output image layers can be derived also in stereo anaglyph mode, allowing a thorough 3-dimensional perception of the landscape morphology as derived by the input elevation dataset. This method is here applied to two test cases showing the performances of the procedure. A website is also addressed where seamless perspective and stereo views of the landscape of the Italian territory preserving the input 10 m or 5 m resolution can be examined

A website to explore the TINITALY/01 DEM

In 2007, a new digital elevation model (DEM) of the whole Italian territory, named TINITALY/01, was presented by Tarquini et al. [2007]. This DEM was the final result of the DIGITALIA project supported by the Italian Ministero dell’Ambiente e della Tutela del Territorio in the framework of a general agreement involving the Istituto Nazionale di Geofisica e Vulcanologia (INGV). The whole database of this DEM, in the form of a 10 m cell size grid, is available to the INGV research community at the web portal Kharita (http://kharita.rm.ingv.it/dmap/). Tarquini et al. [2007] mentioned in short a dedicated website (http://webgis.pi.ingv.it/), where authorized users were allowed to explore full resolution nadiral or perspective shaded relief images (in stereo or conventional format) obtained from the TINITALY/01 DEM. The navigation of this website is now opened to the public. The present technical report illustrates this website, describing its content and unfolding related technological aspects

Multiview 3D reconstruction in geosciences

Multiview three-dimensional (3D) reconstruction is a technology that allows the creation of 3D models of a given scenario from a series of overlapping pictures taken using consumer-grade digital cameras. This type of 3D reconstruction is facilitated by freely available software, which does not require expert-level skills. This technology provides a 3D working environment, which integrates sample/field data visualization and measurement tools. In this study, we test the potential of this method for 3D reconstruction of decimeter-scale objects of geological interest. We generated 3D models of three different outcrops exposed in a marble quarry and two solids: a volcanic bomb and a stalagmite. Comparison of the models obtained in this study using the presented method with those obtained using a precise laser scanner shows that multiview 3D reconstruction yields models that present a root mean square error/average linear dimensions between 0.11 and 0.68%. Thus this technology turns out to be an extremely promising tool, which can be fruitfully applied in geosciences

Release of a 10-m-resolution DEM for the Italian territory: Comparison with global-coverage DEMs and anaglyph-mode exploration via the web

The 10-m-resolution TINITALY/01 DEM (Tarquini et al., 2007) is compared with the two, coarser-resolution, global-coverage, spaceborne-based SRTM and ASTER DEMs and with a high-resolution, LIDAR-derived DEM. Afterwards, we presented a webGIS which allows to explore a 10-m-resolution anaglyph layer showing the landforms of the whole Italian territory in 3D. The webGIS (http://tinitaly.pi.ingv.it/) is open to the public, and can be used to carry out a preliminary analysis of landforms. The TINITALY/01 DEM is available for scientific purposes on the basis of a research agreement (see the above website or write to [email protected])

The Impact of 234U α-emission Induced Radiolysis on UF6 Storage Composition for Non-destructive Verification via Passive Neutron Counting

The mass of 235 U present in storage cylinders containing low enriched uranium (LEU) in the form of uranium hexafluoride (UF 6) may be verified nondestructively using a combination of gamma-ray based enrichment meter and passive neutron counting techniques. A hypothetical concern is that the (α,n) production rate in aged bulk UF 6 might differ from that of fresh material if the chemical composition changes over time, the thought being that this could be initiated by the self-induced radiation field, the process known as radiolysis. To support the physics-based interpretation of the observations Croft et al. measured, in 2020, for the specific 234 U-driven (α,n)-yield in UF 6, this work reviews available literature to quantify the possible impact of radiolysis on (α,n) production rate. Building on the review, a radiochemical yield value, G = 0.5 molecules of F 2 per 100 eV is selected, to calculate the impact of UF5 production – via radiolysis – on the (α,n)-yield. Calculations demonstrate a negligible impact on bulk UF 6 concentration and respective neutron yield

First evaluation of neutron induced single event effects on the CMS barrel muon electronics

Neutron irradiation tests of the currently available electronics for the CMS barrel muon detector were performed using Thermal and fast neutrons at E< 11MeV. The Single Event Upset rate on the Static RAM was measured, while upper limits are derived for events having experienced no failure. The results are used to guess the upper limits on the mean time between failures in the whole barrel muon detector

POS0048 SEROPREVALENCE OF ANTI-SARS-COV-2 ANTIBODIES IN RHEUMATIC PATIENTS TREATED WITH BIOLOGICAL AND TARGETED THERAPY LIVING IN LOMBARDY, ITALY (MAINSTREAM PROJECT)

Background:Emerging observational data have shown that rheumatic patients seem not to be more susceptible to SARS-CoV-2 infection neither to worse outcomes. However, the true prevalence of COVID19 is still unknown due to the high proportion of subclinical infection. In this scenario, measuring the seroprevalence of SARS-CoV-2 may be crucial to improve the knowledge about the impact of COVID19 in rheumatic patients.Objectives:To estimate in a COVID19 high-endemic area (Lombardy, Italy) the prevalence of anti-SARS-CoV-2 antibodies in a large cohort of patients with rheumatoid arthritis (RA) or spondyloarthritis (SpA) treated with biologic (b-) or targeted synthetic (ts-) disease modifying drugs (DMARDs).Methods:A seroprevalence cross-sectional study was conducted in the period between 4th May and 16th June 2020, including patients with confirmed RA or SpA treated with b- or tsDMARDs. Patients were tested for anti-SARS-CoV-2 IgG, IgM and IgA antibodies against main viral antigens (nucleoprotein [N], spike 1 [S1], receptor-binding domain [RBD]) using ELISA. These data were compared with those observed in the healthy population in the same period and region. Patients also answered a questionnaire on history of symptoms consistent with COVID19, risk factors and comorbidities. Serological response to RBD was evaluated according to symptom severity (asymptomatic, minor, or major [respiratory and fever >37.5°C] symptoms).Results:The study population included 300 patients (62% females, mean age 53 years, 20% over 65 years old) diagnosed with RA (56%), psoriatic arthritis (23%), or ankylosing spondylitis (21%), treated with anti-TNF (57%), abatacept (20%), anti-IL6 (11%), or JAK inhibitors (5%). Four patients (1.3%) referred a prior diagnosis of COVID19 defined by nasopharyngeal swab. Immunoglobulin titers were evaluated resulting in 9%, 13.6%, and 13.3% positive patients for IgG, IgM and IgA, respectively (Table 1), with no significant difference to the healthy population. Among seropositive patients, 55.3% were asymptomatic, 16% had minor and 19.6% major symptoms, 7.1% were hospitalized. No deaths or admission to intensive care units occurred. IgM, IgG and IgA titers to RBD were higher in patients with both minor and major symptoms compared with asymptomatic ones (Figure 1). No differences were found between seronegative and seropositive patients in relation to age, sex, rheumatic diagnosis, and treatments with b- or tsDMARDs. A relative lower risk of seropositivity was observed in patients receiving concomitant methotrexate (RR 0.49, 95% CI 0.25-0.94; p 0.04), while an increased risk was associated with obesity (RR 2.33, 95% CI 1.26-3.79; p 0.019) and presence of at least 2 comorbidities (RR 1.94, 95% CI 1.11-3.15; p 0.037). Corticosteroids use was numerically more frequent in seropositive than seronegative patients (18% vs 14%).Conclusion:This study confirms that, even in a cohort of rheumatic patients, the spread of SARS-CoV-2 infection is much greater than that observed by capturing only swab-diagnosed COVID19 cases. The underlying rheumatic disease and ongoing therapy with b/ts-DMARDs do not seem to impact SARS-CoV-2 antibody positivity, which conversely seems to be proportional to the intensity of COVID19 symptoms and less frequent in patients receiving concomitant methotrexate. The project was co-financed by Lombardy Region 2014-2020 Regional Operational Programme under the European Regional Development Fund.Table 1.Prevalence of specific anti-SARS-CoV-2 antibodies.AntibodiesPosivite(n)Seroprevalence (%)(95% CI)IgG279%(6.2 – 12.7)IgG anti-N268.6%(5.9 – 12.3)IgG anti-RBD206.6%(4.3 – 10)IgG anti-S1186%(3.8 – 9.2)IgM4113.6%(10.2 – 18)IgM anti-N3511.6%(8.5 – 15.7)IgM anti-RBD258.3%(5.7 – 12)IgA4013.3%(9.9 – 17.6)IgA anti-N3712.3%(9.0 – 16.5)IgA anti-RBD258.3%(5.7 – 12)IgG+IgM237.6%(5.1 – 11.2)IgG+IgM+IgA227.3%(4.9 – 10.5)IgG+IgA248%(5.4 – 11.6)IgG/IgM/IgA5618.6%(14.6 – 23.4)Figure 1.Antibody levels (S/Co) against SARS-CoV-2 RBD.Disclosure of Interests:None declared