1,016 research outputs found
Investigating the Internal Deterioration of the Auriga Statue of Mozia Island, Sicily, through Ultrasonic and Ground-Penetrating Radar Studies
No full textThe Greek marble statue of the Auriga of Mozia Island, in Sicily, is the most important artwork displayed at the Whitaker Foundation Archaeological Museum. It underwent geophysical investigations twice, in 2012 and 2021, to assess the marble’s degradation. The 2012 investigation prepared the statue for transfer to the Paul Getty Museum in New York and repositioning on an anti-seismic pedestal. The 2021 investigation evaluated potential new damage before another transfer. Both investigations utilized 3D ultrasonic tomography (UST) to detect degraded marble areas and ground-penetrating radar (GPR) to identify internal discontinuities, such as fractures or lesions, and locate metal pins that were previously inserted to reassemble the statue and its pedestal. Results from the UST indicate an average marble velocity of approximately 4700 m/s, suggesting good mechanical strength, with some areas showing lower velocities (~3000 m/s) within the material’s variability range. The GPR profiles demonstrated internal signal homogeneity, excluding internal fracture surfaces or lesions, and confirmed the presence of metallic pins. This study highlights the effectiveness of integrating UST and GPR for non-invasive diagnostics of marble sculptures, providing detailed insights into the marble’s condition and identifying hidden defects or damage
Chronic renal failure: oxidative stress, endothelial dysfunction and wine
No full textAtherosclerosis development is accelerated in chronic renal failure (CRF) and is the major cause of death in this clinical condition. An increased oxidative stress and an endothelial dysfunction, with their complex interrelationships, are relevant aspects of atherogenesis in CRF patients and might be targets for treatment. Many studies have underlined the cardiovascular protection provided by a moderate wine consumption. This beneficial effect is due to both alcohol and nonalcoholic components of wine including several phenolic molecules such as quercetin and resveratrol. Wine polyphenols have antioxidant properties and favorably influence endothelial function, in particular by stimulating nitric oxide-mediated vasodilation and inhibiting the endothelin-1 pathway. The possible advantage of a moderate wine consumption in CRF patients can be hypothesized and deserves clinical investigation
Misinterpretation caused by 3D effects on 2D Electrical Resistivity Tomography: tests on simple models
No full textThe aim of this work is to evaluate the effects of 2D inversion of electrical resistivity data when in presence on 3D structures by testing synthetic and experimental models. Several numerical simulations have been calculated for different resistivity models and 2D datasets were extracted to study and quantify the effects of 2D inversion on 3D structures. Results have been compared with field texts carried out in quarrying sites. The main tests here presented simulates prism-shaped cavities with a square vertical section of l x l size and a variable lateral extension d, from l to infinity (this latter being a 2D tunnel model). Inversion of predicted data show that 2D tomography does not always give satisfactory results on cavities that have a more or less limited extension perpendicular to the profile. In all cases the resistivity anomaly obtained by the 2D inversion of a 3D cavity underestimates the true value much more than the inversion of the corresponding 2D model and obviously underestimation increases with three-dimensional characteristics. The effects of three-dimensionality can lead to the identification of false cavities along the vertical or can lead to strong errors in the estimation of depth and size, thus causing misleading statements
Quantum spin chain dissipative mean-field dynamics
No full textWe study the emergent dynamics resulting from the infinite volume limit of the mean-field dissipative dynamics of quantum spin chains with clustering, but not time-invariant states. We focus upon three algebras of spin operators: the commutative algebra of mean-field operators, the quasi-local algebra of microscopic, local operators and the collective algebra of fluctuation operators. In the infinite volume limit, mean-field operators behave as time-dependent, commuting scalar macroscopic averages while quasi-local operators, despite the dissipative underlying dynamics, evolve unitarily in a typical non-Markovian fashion. Instead, the algebra of collective fluctuations, which is of bosonic type with time-dependent canonical commutation relations, undergoes a time-evolution that retains the dissipative character of the underlying microscopic dynamics and exhibits non-linear features. These latter disappear by extending the time-evolution to a larger algebra where it is represented by a continuous one-parameter semigroup of completely positive maps. The corresponding generator is not of Lindblad form and displays mixed quantum-classical features, thus indicating that peculiar hybrid systems may naturally emerge at the level of quantum fluctuations in many-body quantum systems endowed with non time-invariant states
Quantum fluctuations in mesoscopic systems
No full textRecent experimental results point to the existence of coherent quantum phenomena in systems made of a large number of particles, despite the fact that for many-body systems the presence of decoherence is hardly negligible and emerging classicality is expected. This behaviour hinges on collective observables, named quantum fluctuations, that retain a quantum character even in the thermodynamic limit: they provide useful tools for studying properties of many-body systems at the mesoscopic level, in-between the quantum microscopic scale and the classical macroscopic one. We herein present the general theory of quantum fluctuations in mesoscopic systems, and study their dynamics in a quantum open system setting, taking into account the unavoidable effects of dissipation and noise induced by the external environment. As in the case of microscopic systems, decoherence is not always the only dominating effect at the mesoscopic scale: certain types of environment can provide means for entangling collective fluctuations through a purely noisy mechanism
Long-lived mesoscopic entanglement between two damped infinite harmonic chains
No full textAbstract We consider two chains, each made of N independent oscillators, immersed in a common thermal bath and study the dynamics of their mutual quantum correlations in the thermodynamic, large-N limit. We show that dissipation and noise due to the presence of the external environment are able to generate collective quantum correlations between the two chains at the mesoscopic level. The created collective quantum entanglement between the two many-body systems turns out to be rather robust, surviving for asymptotically long times even for non vanishing bath temperatures
Infrastructural Projects and Territorial Development in Veneto Dolomites: Evaluation of Performances through AHP
No full textAbstractThe ensemble of European traffic roads is changing in relation to the economic geography that has been developing these recent years and also to the localisation of production centres, logistics and the demand linked to the transportation of goods. The development of communication has been defined through the project of the Trans-European Transport Network (TEN-T). This network has been progressively defined until it has reached the present architecture in which Italy is crossed by four of the nine total corridors that compose the whole network - which means by almost half of the main traffic roads at European level -. Undoubtedly this new geography of European communication offers member States new development opportunities, but it is also true that the distance of the different territories from the major traffic roads can be a disparity factor. In fact, this phenomenon can worsen the marginalisation processes of some European territories, contrary to the objective of the interconnection policy of the EU territories. In front of these possible territorial disparities, the Planning discipline in Italy has not been adequately questioned, aiming instead at the research of the “territorial patching up”, progressively decreasing, rather than at the exploration of new development forms. As a consequence, mobility planning becomes strategic for Italy, especially for its Alpine area. Hence the need to set up valid tools for the environmental evaluation as regards planning and programmes, such as the Strategic Environmental Assessment (SEA), but also projects, as the Environmental Impact Assessment (EIA). The idea to realise an important road infrastructure, which may connect Belluno directly with Austria, is presented in this paper as an emblematic case, in which the application of the Analytic Hierarchy Process (AHP) permits to verify the best performing infrastructure on a territorial scale
Cluster Analysis for Cavity Detection Using Seismic Refraction and Electrical Resistivity Tomography
No full textGeophysical methods (in particular ERT technique) constitute an excellent tool for the detection of buried
cavities. However the integration approach of e different geophysical methods could minimize the ambiguity of
geophysical interpretation of the buried cavity. The technique of electrical tomography has been joined to the
technique of seismic refraction tomography in order to obtain more robust interpretations. Many tests have been
carried out using synthetic data and experimental ones. It was finally used a statistical approach based on cluster
analysis of the P-wave velocity, the density of the seismic rays and the electrical resistivity of the synthetic and
experimental models. Distribution maps of the cluster in multi-space were built, allowing to better define and
interpret the anomalies of the subsoil
Pathophysiological and clinical aspects of malnutrition in chronic renal failure
No full textKidney diseases are the ninth leading cause of death in the USA. In these patients cardiovascular mortality is greater than in the general population. This observation, not completely explained by the so-called 'traditional' cardiovascular risk factors, lead the authors to postulate other 'emerging' ones found in chronic renal failure patients. Among these new findings, nutritional status, considered as the balance existing between nutrient requirements and intakes, plays an important role for the development of cardiovascular diseases. In fact several nutritional parameters are widely known as pathophysiological determinants of cardiovascular disturbances, which are based on accelerated atherosclerosis, due especially to enhanced oxidative stress and endothelial dysfunction. Chronic renal failure is a clinical condition that from many points of view seems to be a chronic inflammatory state, and many studies confirm this observation. This influences nutritional status especially in dialysis patients. Malnutrition is related in turn to accelerated atherosclerosis thus leading to a postulated 'malnutrition, inflammation, atherosclerosis' (MIA) syndrome in which malnutrition, inflammation and atherosclerosis contribute to an elevated cardiovascular mortality rate. The present review explores this issue, first by describing epidemiological aspects of malnutrition in chronic renal failure patients and then by analysing the specific biochemical and metabolic features of these patients
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