1,721,089 research outputs found
MODSIM-P: Il nuovo modello dinamico di previsione della spesa pensionistica. Formalizzazione algebrica delle relazioni di funzionamento, struttura della programmazione, basi di dati
No full textMonitoring and Modeling Tidally Induced Pore-Pressure Oscillations in the Soil of St. Mark's Square in Venice, Italy
Full text linkSea level rise and high tide events are threatening many coastal cities, which require adequate and sustainable protection measures. The historic city centre of Venice (Italy) is often flooded during very high tide events, especially the area of St. Mark's Island, which is at the lowest elevation among all the islands forming the city. To design cost-effective protection interventions to safeguard the historical heritage, a deep understanding of flooding mechanisms and the relationship between groundwater pressure and tidal oscillations is necessary. Geotechnical survey and analyses play an important role in this process. This paper presents the results of a recent monitoring campaign carried out in St. Mark's Island. A simplified one-dimensional analytical model was derived for saturated conditions to understand the key parameters that govern tidal induced pressure oscillations in soil (material properties, geometrical features, and wave properties). Additional features, such as partially saturated soil conditions and two-dimensional effects, were investigated numerically. Results showed that significant pressure oscillations occur in the subsoil, which should not be neglected when considering the stability of horizontal architectural structures, such as the historical mosaics and paving. However, seepage flow rate is small, and thus its impact on the drainage system is limited in terms of water discharge
Applicability of CPTU to characterize diatomaceous fine-grained soils: a case study in Euganean Hills (Italy)
Full text linkDiatomaceous soils, composed of diatom fossils and clay minerals typically formed in volcanic environments, exhibit characteristics such as low unit weight, high plasticity and liquid limit, significant compressibility, and high friction angles. Despite their presence in various locations globally, knowledge about their geotechnical behavior is limited and primarily based on laboratory tests conducted on artificial samples. This paper presents data obtained from undisturbed samples of natural diatomaceous soils and discusses the interpretation of Cone Penetration Test with Pore Pressure (CPTU) data to classify these complex non-textbook soils and estimate their mechanical properties.
The study area is situated in the Po Plain near the thermal anomaly region of the Euganean Hills in Northeast Italy. Three CPTUs and one borehole with the collection of four Osterberg undisturbed samples were conducted. Laboratory tests on the undisturbed samples provided values for Atterberg Limits, soil unit weight, in-situ void ratio, compressibility, and permeability, which were compared with estimations derived from CPTU data analysis. Moreover, Scanning Electron Microscope images provided insight into the distinctive microstructure of diatom microfossils embedded in a clayey matrix.
Based on these comparisons, CPTU proves to be effective in estimating relevant parameters of diatomaceous soils, particularly the Soil Behavior Type (SBT) and consolidation coefficient from dissipation tests. However, the agreement in estimating the oedometric modulus is less satisfactory. Therefore, for a precise definition of the geotechnical model, it is recommended to conduct additional laboratory tests, particularly those focused on defining compressibility parameters, given the unique behavior of natural diatomaceous soils
Who and how to screen for endogenous hypercortisolism in a high-risk population: a special issue of the journal of endocrinological investigations
No full textModellazione del collasso arginale indotto da sollevamento al piede con il metodo dei punti materiali
Full text linkIn questo contributo viene indagato un tipico meccanismo di collasso arginale, indotto da sovrapressioni nei terreni di fondazione. Tale meccanismo è caratterizzato dal sollevamento al piede dell’argine e da una perdita di resistenza che può favorire localizzazione di deformazioni e lo scivolamento profondo. Una possibile conseguenza è la propagazione della superficie di rottura con l’interessamento del corpo arginale, e la formazione di una triplice superficie di scorrimento di forma non circolare. Questo fenomeno complesso viene per la prima volta analizzato mediante il Metodo dei Punti Materiali (MPM) che consente l’analisi delle fasi di formazione della superficie di scivolamento e collasso, senza i vincoli degli approcci agli elementi finiti (FEM).
Attraverso la riproduzione di un esperimento in centrifuga geotecnica, il contributo si propone di testare l’abilità dell’MPM come strumento predditivo di questo tipo di fenomeno e di supportare analisi di rischio affidabili, non troppo conservative. Il confronto con approcci numerici convenzionali supporta la tesi e conclude il contributo
Characterization of geotechnical spatial variability in river embankments from spatially adjacent SCPT
Full text linkMonogenic Forms of Hypertension
No full textEssential hypertension is a highly prevalent disease in the general population. Secondary hypertension is characterized by a specific and potentially reversible cause of increased blood pressure levels. Some secondary endocrine forms of hypertension are common (caused by uncontrolled cortisol, aldosterone, or catecholamines production). This article describes rare monogenic forms of hypertension, characterized by electrolyte disorders and suppressed renin-aldosterone axis. They represent simple models for the physiology of renal control of sodium levels and plasma volume, thus reaching a high scientific interest. Furthermore, they could explain some features closer to the essential phenotype of hypertension, suggesting a mechanistically driven personalized treatment
Exploring the Interaction Between Landslides and Carbon Stocks in Italy
Full text linkLandslides, as natural hazards, have far-reaching impacts beyond their immediate effects on human lives and infrastructure; landslides disrupt both carbon storage and ecosystem stability, and their role in the global carbon cycle cannot be underestimated. This study delves into the complex relationship between landslides and carbon stocks such as, in particular, soil organic carbon (SOC) and above-ground biomass (AGB), and outlines the spatial relationship between different types of landslides, soil organic carbon (SOC), and the carbon cycle, underscoring the importance of understanding these interconnections for environmental sustainability and climate change mitigation efforts. By employing machine learning algorithms on the Google Earth Engine platform, landslide susceptibility maps were created for different landslide types across Italy, and their spatial patterns with SOC accumulation were analyzed using the Python environment. The findings reveal a nuanced relationship between landslide hazard levels and SOC dynamics, with varying trends observed for different landslide types. In addition, this study investigates the potential impact of large-scale landslide events on carbon sequestration in the short term via a case study of the May 2023 landslide event in the Emilia Romagna region of Italy. The analysis reveals a substantial reduction in above-ground biomass by 35%, which approximately accounts for the loss of 0.133 MtC, and a decrease in SOC accumulation in 72% of the affected areas, indicating that landslides can transform carbon sinks into carbon sources, at least in the short term, and suggested that carbon released from extreme landslide events at a larger scale needs to be accounted for in regional or national carbon emissions. This research underscores the importance of considering landslides in carbon cycle assessments and emphasizes the need for sustainable land management strategies to protect and enhance carbon sinks, such as forests and healthy soils, in the face of increasing natural hazards and climate change impacts
Shortage of hCRH for the diagnosis of endogenous CS: the end of an era or the beginning of a new journey?
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