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A Numerical Investigation of Lateral Spreading Phenomena in River Embankments

Emilia region was struck by an earthquake the 20th of May 2012. The seismic event caused a number of liquefaction evidences. A river embankment close to Scortichino village experienced longitudinal cracks and lateral movements. An analysis for evaluation of liquefaction susceptibility is performed based on in-situ tests. CPTU and Vs based methods havve been used and have provided some critical layers at the base of the embankment and on the sandy layer located at a depth of 8 m from ground surface. There is however some uncertainities about the soil liqeufaction susceptibility due to the fact that factor of safety is slightly lower than 1. A numerical analysis is then required to obtain more refined results. An advanced soil constitutive model is used and implemented through the finite element computational platform Opensees to perform a 2D analysis

Lack of a relationship between circulating gamma-glutamyltransferase levels and carotid intima media thickness in hypertensive and diabetic patients

Marco Nuti, Paolo Spontoni, Chrysanthos Grigoratos, Giulia Dell'Omo, Alberto Balbarini, Roberto PedrinelliDipartimento Cardio Toracico e Vascolare, Università di Pisa, Pisa, ItalyBackground: By increasing the intracellular prooxidant burden, gamma-glutamyltransferase (GGT) may accelerate atherosclerotic vascular disease. That noxious influence may be reflected by circulating enzyme levels, a correlate of cardiovascular risk factors, and a predictor of incident events. To evaluate this hypothesis, we tested the association between circulating GGT and common carotid intima-media thickness (CIMT), a surrogate index of systemic atherosclerotic involvement, in a large and well-characterized group of patients at risk of cardiovascular disease (CVD).Patients: This study analyzed 548 patients with hypertension and/or diabetes and a widely prevalent history of CVD. Subjects with known hepatic disease and abnormal GGT values were excluded.Methods: CIMT (B-mode ultrasonography) values were the mean of four far-wall measurements at both common carotids. Metabolic syndrome (MetS) was diagnosed according to National Cholesterol Education Program-Adult Treatment Panel III criteria. Due to inherent sex-related differences in GGT levels, the data were analyzed separately in males and females in samples dichotomized by the median.Results: The age-adjusted CIMT values did not differ by GGT levels in males or females. In contrast, the carotid wall was consistently thicker in patients with a history of CVD and MetS independent of age and concurrent GGT values. In both sexes, GGT was associated with key components of the MetS such as triglycerides, fasting plasma glucose, and body mass index.Conclusion: The data collected in this mixed group of hypertensive and/or diabetic patients with widely prevalent history of CVD do not support the concept of a direct pathophysiological link between GGT levels within reference limits and atherosclerotic involvement.Keywords: gamma-glutamyltransferase, carotid intima-media thickness, atherosclerosis, metabolic syndrom

An uncommon clinical condition: chronic thrombosis of the inferior vena cava. A case report and review of literature

The lifetime incidence of deep vein thrombosis (DVT) is approximately 0.1% in general population and even more uncommon in subjects below 40 years of age. Thrombosis of the inferior vena cava (IVC) is an exceptionally rare clinical condition, with etiological factors similar to lower limb DVT. We present a case of post-traumatic chronic obstruction of the IVC in 41 years-old man, caused by a prolonged squatted position, while he was working as a bricklayer. We visited the patient fifteen years after the onset of the first clinical setting showing a severe post thrombotic syndrome, as a consequence of the already diagnosticated thrombosis, involving predominantly the right inferior leg. Thrombophilia screening tests showed patient to be a heterozygous carrier of methylenetetrahydrofolate reductase (MTHFR) gene mutation. Computed tomography (CT) scan confirmed the thrombotic obstruction of the infrahepatic IVC, both common iliac veins, right external and internal iliac veins, with multiple collateral pathways. Because of thrombosis extension, inherited prothrombotic condition and the young age of the patient, we decided to continue life-long oral anticoagulant therapy

Detailed landfill leachate plume mapping using 2D and 3D electrical resistivity tomography - with correlation to ionic strength measured in screens

Leaching of organic and inorganic contamination from landfills is a serious environmental problem as surface water and aquifers are affected. In order to assess these risks and investigate the migration of leachate from the landfill, 2D and large scale 3D electrical resistivity tomography were used at a heavily contaminated landfill in Grindsted, Denmark. The inverted 2D profiles describe both the variations along the groundwater flow as well as the plume extension across the flow directions. The 3D inversion model shows the variability in the low resistivity anomaly pattern corresponding to differences in the ionic strength of the landfill leachate. Chemical data from boreholes agree well with the observations indicating a leachate plume which gradually sinks and increases in size while migrating from the landfill in the groundwater flow direction. Overall results show that the resistivity method has been very successful in delineating the landfill leachate plume and that good correlation exists between the resistivity model and leachate ionic strength

A 3-D numerical model of the influence of meanders on groundwater discharge to a gaining stream in an unconfined sandy aquifer

Groundwater discharge to streams depends on stream morphology and groundwater flow direction, but are not always well understood. Here a 3-D groundwater flow model is employed to investigate the impact of meandering stream geometries on groundwater discharge to streams in an unconfined and homogenous sandy aquifer at the reach scale (10–200 m). The effect of meander geometry was examined by considering three scenarios with varying stream sinuosity. The interaction with regional groundwater flow was examined for each scenario by considering three groundwater flow directions. The sensitivity of stream morphology and flow direction to other parameters was quantified by varying the stream width, the meander amplitude, the magnitude of the hydraulic gradient, the hydraulic conductivity, and the aquifer thickness. Implications for a real stream were then investigated by simulating groundwater flow to a stream at a field site located in Grindsted, Denmark. The simulation of multiple scenarios was made possible by the employment of a computationally efficient coordinate transform numerical method. Comparison of the scenarios showed that the geometry of meanders greatly affect the spatial distribution of groundwater flow to streams. The shallow part of the aquifer discharges to the outward pointing meanders, while deeper groundwater flows beneath the stream and enters from the opposite side. The balance between these two types of flow depends on the aquifer thickness and meander geometry. Regional groundwater flow can combine with the effect of stream meanders and can either enhance or smooth the effect of a meander bend, depending on the regional flow direction. Results from the Grindsted site model showed that real meander geometries had similar effects to those observed for the simpler sinuous streams, and showed that despite large temporal variations in stream discharge, the spatial pattern of flow is almost constant in time for a gaining stream