Application of surface-wave tomography to mineral exploration : a case study from Siilinjarvi, Finland

In order to assess the feasibility and validity of surface-wave tomography as a tool for mineral exploration, we present an active seismic three-dimensional case study from the Siilinjarvi mine in Eastern Finland. The aim of the survey is to identify the formation carrying the mineralization in an area south of the main pit, which will be mined in the future. Before acquiring the data, we performed an accurate survey design to maximize data coverage and minimize the time for deployment and recollection of the equipment. We extract path-averaged Rayleigh-wave phase-velocity dispersion curves by means of a two-station method. We invert them using a computationally efficient tomographic code which does not require the computation of phase-velocity maps and inverts directly for one-dimensional S-wave velocity models. The retrieved velocities are in good agreement with the data from a borehole in the vicinity, and the pseudo three-dimensional S-wave velocity volume allows us to identify the geological contact between the formation hosting most of the mineralization and the surrounding rock. We conclude that the proposed method is a valid tool, given the small amount of equipment used and the acceptable amount of time required to process the data.Peer reviewe

Beta-Blocker Use in Older Hospitalized Patients Affected by Heart Failure and Chronic Obstructive Pulmonary Disease: An Italian Survey From the REPOSI Register

Beta (β)-blockers (BB) are useful in reducing morbidity and mortality in patients with heart failure (HF) and concomitant chronic obstructive pulmonary disease (COPD). Nevertheless, the use of BBs could induce bronchoconstriction due to β2-blockade. For this reason, both the ESC and GOLD guidelines strongly suggest the use of selective β1-BB in patients with HF and COPD. However, low adherence to guidelines was observed in multiple clinical settings. The aim of the study was to investigate the BBs use in older patients affected by HF and COPD, recorded in the REPOSI register. Of 942 patients affected by HF, 47.1% were treated with BBs. The use of BBs was significantly lower in patients with HF and COPD than in patients affected by HF alone, both at admission and at discharge (admission, 36.9% vs. 51.3%; discharge, 38.0% vs. 51.7%). In addition, no further BB users were found at discharge. The probability to being treated with a BB was significantly lower in patients with HF also affected by COPD (adj. OR, 95% CI: 0.50, 0.37-0.67), while the diagnosis of COPD was not associated with the choice of selective β1-BB (adj. OR, 95% CI: 1.33, 0.76-2.34). Despite clear recommendations by clinical guidelines, a significant underuse of BBs was also observed after hospital discharge. In COPD affected patients, physicians unreasonably reject BBs use, rather than choosing a β1-BB. The expected improvement of the BB prescriptions after hospitalization was not observed. A multidisciplinary approach among hospital physicians, general practitioners, and pharmacologists should be carried out for better drug management and adherence to guideline recommendations

Clinical features and outcomes of elderly hospitalised patients with chronic obstructive pulmonary disease, heart failure or both

Background and objective: Chronic obstructive pulmonary disease (COPD) and heart failure (HF) mutually increase the risk of being present in the same patient, especially if older. Whether or not this coexistence may be associated with a worse prognosis is debated. Therefore, employing data derived from the REPOSI register, we evaluated the clinical features and outcomes in a population of elderly patients admitted to internal medicine wards and having COPD, HF or COPD + HF. Methods: We measured socio-demographic and anthropometric characteristics, severity and prevalence of comorbidities, clinical and laboratory features during hospitalization, mood disorders, functional independence, drug prescriptions and discharge destination. The primary study outcome was the risk of death. Results: We considered 2,343 elderly hospitalized patients (median age 81 years), of whom 1,154 (49%) had COPD, 813 (35%) HF, and 376 (16%) COPD + HF. Patients with COPD + HF had different characteristics than those with COPD or HF, such as a higher prevalence of previous hospitalizations, comorbidities (especially chronic kidney disease), higher respiratory rate at admission and number of prescribed drugs. Patients with COPD + HF (hazard ratio HR 1.74, 95% confidence intervals CI 1.16-2.61) and patients with dementia (HR 1.75, 95% CI 1.06-2.90) had a higher risk of death at one year. The Kaplan-Meier curves showed a higher mortality risk in the group of patients with COPD + HF for all causes (p = 0.010), respiratory causes (p = 0.006), cardiovascular causes (p = 0.046) and respiratory plus cardiovascular causes (p = 0.009). Conclusion: In this real-life cohort of hospitalized elderly patients, the coexistence of COPD and HF significantly worsened prognosis at one year. This finding may help to better define the care needs of this population

Analysis of the Seismic Properties for Engineering Purposes of the Shallow Subsurface: Two Case Studies from Italy and Croatia

We present two case studies of the application of seismic surveys to estimate the elastic properties of soil and rock in the shallow subsurface. The two sites present very different geological characteristics. The first test site is a town on the Croatian coast, not far from the city of Split, built on hard rock, where we acquired three seismic lines. The second site is located in the outskirts of the city of Ferrara, in Italy, in an alluvial plain, where two lines were acquired. In both sites, for detailed characterization, we acquired surface-, compressional- and shear-waves, further distinguishing the latter between horizontally (SH) and vertically (SV) polarized wavefields. We processed the data by performing a Multichannel Analysis of Surface Waves to compute a preliminary one-dimensional shear wave velocity profile. Then, we performed first-break tomography to compute P-, SH- and SV-velocity profiles. Such unusual acquisition allowed us to compute not only basic engineering parameters such as the equivalent shear-wave velocity of the first 30 m of subsurface (VS30) from the SH profiles but also other useful parameters such as the VP/VS and estimate the anisotropy of the medium thanks to the VSV/VSH. Given the level of detail of the results and their engineering value, we conclude that the method of investigation we applied in the two test sites is a valuable tool for characterizing the shallow subsurface

Modelling Techniques to Monitor the Injection of Carbon Dioxide in Deep Saline Aquifers

In this thesis we want to model all steps of a CO2 injection in deep saline aquifers, from the injection to the monitoring by means of seismic methods. After outlining the main physical and chemical processes which allow the CO2 to be trapped for very long periods of time, we present two numerical examples. In the first one, CO2 is injected in a complex aquifer, part of an anticlinal structure, with characteristics resembling those of the Sleipner field. The injection is monitored via an active cross-hole seismic experiment; in particular, we perform a tomographic inverion of the direct arrivals. In the second example, CO2 is injected at a constant rate for one hour in a homogenous aquifer. It is then monitored with a passive seismic method. In fact, the overpressure caused by the injection, may lead to the formation of microcracks and therefore to the emission of seismic waves. We approximate the position of the CO2 plume by finding these emitting points by means of a reverse-time migration algorithm

Analysis of the Seismic Properties for Engineering Purposes of the Shallow Subsurface: Two Case Studies from Italy and Croatia

We present two case studies of the application of seismic surveys to estimate the elastic properties of soil and rock in the shallow subsurface. The two sites present very different geological characteristics. The first test site is a town on the Croatian coast, not far from the city of Split, built on hard rock, where we acquired three seismic lines. The second site is located in the outskirts of the city of Ferrara, in Italy, in an alluvial plain, where two lines were acquired. In both sites, for detailed characterization, we acquired surface-, compressional- and shear-waves, further distinguishing the latter between horizontally (SH) and vertically (SV) polarized wavefields. We processed the data by performing a Multichannel Analysis of Surface Waves to compute a preliminary one-dimensional shear wave velocity profile. Then, we performed first-break tomography to compute P-, SH- and SV-velocity profiles. Such unusual acquisition allowed us to compute not only basic engineering parameters such as the equivalent shear-wave velocity of the first 30 m of subsurface (VS30) from the SH profiles but also other useful parameters such as the VP/VS and estimate the anisotropy of the medium thanks to the VSV/VSH. Given the level of detail of the results and their engineering value, we conclude that the method of investigation we applied in the two test sites is a valuable tool for characterizing the shallow subsurface

Surface wave tomography to retrieve near surface velocity models

Surface-wave tomography is usually applied at regional or planetary scale but represent an interesting approach also for near surface applications. We present a surface wave dispersion tomography that does not require the construction of phase or group velocity maps and which inverts path-specific dispersion data directly for 3-D Swave velocity variations. To compare it with classical multichannel surface-wave analysis we here present the application to a 2D seismic line

What changed in the Italian internal medicine and geriatric wards during the lockdown

Not availabl

Underdiagnosis and undertreatment of osteoporotic patients admitted in internal medicine wards in Italy between 2010 and 2016 (the REPOSI Register)

To evaluate clinical features, treatments, and outcomes of osteoporotic patients admitted to internal medicine and geriatric wards compared with non-osteoporotic patients (REPOSI registry)