On the Thermal Activation of Turin Metro Line 2 Tunnels

The Turin metro Line 2 will extend for nearly 28 km and include 26 stations. It will connect the SW suburbs of the city to the NE ones. The excavation will be performed by means of TBM and Cut & Cover techniques and, once concluded, will host a fully automated driverless light metro. This paper will describe the feasibility study carried out to assess the energy potential of the thermal activation of the line by using an innovative tunnel lining segment (ENERTUN) recently patented and tested in real operating conditions. A novel methodology was adopted, involving thermo-hydraulic 3D FE numerical anal- yses to identify the geothermal potential for the different sections of the line. A study of the possible collectors for the thermal energy produced was also performed considering the planned stations, the existing buildings and the future urban developments

Classification of Epileptic Activity Through Temporal and Spatial Characterization of Intracranial Recordings

Focal epilepsy is a chronic condition characterized by hyper-activity and abnormal synchronization of a specific brain region. For pharmacoresistant patients, the surgical resection of the critical area is considered a valid clinical solution, therefore, an accurate localization is crucial to minimize neurological damage. In current clinical routine the characterization of the Epileptogenic Zone (EZ) is performed using invasive methods, such as Stereo-ElectroEncephaloGraphy (SEEG). Medical experts perform the tag of neural electrophysiological recordings by visually inspecting the acquired data, a highly time consuming and subjective procedure. Here we show the results of an automatic multi-modal classification method for the evaluation of critical areas in focal epileptic patients. The proposed method represents an attempt in the characterization of brain areas which integrates the anatomical information on neural tissue, inferred using Magnetic Resonance Imaging (MRI) in combination with spectral features extracted from SEEG recordings

Theoretical Methods for Wave Propagation across Jointed Rock Masses

Different methods are presently available for the analysis of wave propagation across jointed rock masses with the consideration of multiple wave reflections between joints. These methods can be divided into two categories. One is based on the displacement discontinuity model for representing rock joints, where the displacements across a joint are discontinuous and the tractions are continuous, and the other is the equivalent medium method. For the first category, there are three methods, i.e., method of characteristics (MC), scattering matrix method (SMM) and virtual wave source method (VWS). MC solves the equation of motion by using the theory of characteristic curves. SMM is based on the definition of the scattering matrix in which the reflection and transmission coefficients of a set of joints are stored. VWS method replaces the joints in the rock mass with a virtual concept. For the second category, equivalent medium model treats the problem in the frame of continuum mechanics and simplifies it from an explicit wave propagation equation. The objective of this paper is to review and compare these theoretical methods. The comparison shows that the four solutions agree very well with each other. Some additional considerations about the advantages and disadvantages of these methods are also given in the pape

Seismic response of a single and a set of filled joints of viscoelastic deformational behaviour

Rock joints are often filled with weak medium, for example, saturated clay or sand, of viscoelastic nature. Their effects on wave propagation can be modelled as displacement and stress discontinuity conditions. The viscoelastic behaviour of the filled joint can be described by either the Kelvin or the Maxwell models. The analytical solutions for wave propagation across a single joint are derived in this paper by accounting for the incident angle, the non-dimensional joint stiffness, the non-dimensional joint viscosity and the acoustic impedance ratio of the filled joint. It is shown that the viscoelastic behaviour results in dissipation of wave energy and frequency dependence of the reflection and transmission coefficients. Based on curve fitting of the experimental data of P-wave propagation across a single joint filled with saturated sand, both the Kelvin and Maxwell models are found to reproduce the behaviour of the filled joint, in terms of the amplitude and frequency contents. Then, wave transmission across a filled joint set is studied with the virtual wave source method and the scattering matrix method, where multiple wave reflections among joints are taken into account. It is shown that the non-dimensional joint spacing and the number of joints have significant effects on the transmission coefficient

Valence and magnetic instabilities in Sm compounds at high pressures

We report on the study of the response to high pressures of the electronic and magnetic properties of several Sm-based compounds, which span at ambient pressure the whole range of stable charge states between the divalent and the trivalent. Our nuclear forward scattering of synchrotron radiation and specific heat investigations show that in both golden SmS and SmB6 the pressure-induced insulator to metal transitions (at 2 and about 4-7 GPa, respectively) are associated with the onset of long-range magnetic order, stable up to at least 19 and 26 GPa, respectively. This long-range magnetic order, which is characteristic of Sm(3+), appears already for a Sm valence near 2.7. Contrary to these compounds, metallic Sm, which is trivalent at ambient pressure, undergoes a series of pressure-induced structural phase transitions which are associated with a progressive decrease of the ordered 4f moment.Comment: 15 pages (including 7 figures) submitted to J. Phys.: Condens. Matte

Discontinuous Transition from a Real Bound State to Virtual Bound State in a Mixed-Valence State of SmS

Golden SmS is a paramagnetic, mixed-valence system with a pseudogap. With increasing pressure across a critical pressure Pc, the system undergoes a discontinuous transition into a metallic, anti-ferromagnetically ordered state. By using a combination of thermodynamic, transport, and magnetic measurements, we show that the pseudogap results from the formation of a local bound state with spin singlet. We further argue that the transition Pc is regarded as a transition from an insulating electron-hole gas to a Kondo metal, i.e., from a spatially bound state to a Kondo virtually bound state between 4f and conduction electrons.Comment: 5 pages, 5 figure

The hidden information in patient-reported outcomes and clinician-assessed outcomes: multiple sclerosis as a proof of concept of a machine learning approach

Machine learning (ML) applied to patient-reported (PROs) and clinical-assessed outcomes (CAOs) could favour a more predictive and personalized medicine. Our aim was to confirm the important role of applying ML to PROs and CAOs of people with relapsing-remitting (RR) and secondary progressive (SP) form of multiple sclerosis (MS), to promptly identifying information useful to predict disease progression. For our analysis, a dataset of 3398 evaluations from 810 persons with MS (PwMS) was adopted. Three steps were provided: course classification; extraction of the most relevant predictors at the next time point; prediction if the patient will experience the transition from RR to SP at the next time point. The Current Course Assignment (CCA) step correctly assigned the current MS course with an accuracy of about 86.0%. The MS course at the next time point can be predicted using the predictors selected in CCA. PROs/CAOs Evolution Prediction (PEP) followed by Future Course Assignment (FCA) was able to foresee the course at the next time point with an accuracy of 82.6%. Our results suggest that PROs and CAOs could help the clinician decision-making in their practice

Prévalence du VIH chez la Femme Enceinte et Transmission Mère-Enfant du VIH à la Maternité de l’Hôpital Général de Douala, Cameroun

Nous rapportons ici une évaluation sommaire de nos activités de prévention transmission mère-enfant du VIH sur 6 ans (2002 à 2007). Il s’agissait d’une étude descriptive et rétrospective effectuée à l’Hôpital Général de Douala. Les enfants inclus étaient âgés d’au moins 18 mois. La technique d’ELISA GENSCREEN 3ème génération pour le VIH a été utilisée. Sur 5261 accouchements effectués pendant cette période, 138 étaient de mères VIH positifs (prévalence : 2,62%). Quatre de nos patientes étaient testées négatives au premier trimestre de gestation. Des 138 bébés, 87 seulement ont pu être testés (63%), dont 4 contaminés (prévalence de transmission : 4,6%). Des 4 enfants contaminés, un seul a reçu la prévention adéquate en grossesse, soit un taux de transmission sous prévention de 1,19%. Une meilleure organisation des stratégies de réduction de la transmission mèreenfant du VIH/SIDA, même dans un environnement à ressources limitées, peut conduire à des résultats similaires à ceux des pays du Nord. A la lumière de cette étude, nous recommandons fortement un deuxième test du VIH au 3ème rimestre de la grossesse afin de réduire davantage le risque de sa transmission périnatale.Mots Clés prévalence du VIH ; femme enceinte ; transmission mère-enfant du VI

Phase diagram of heavy fermion systems

The Meccano of heavy fermion systems is shown on different cases going from anomalous monochalcogenides to cerium intermetallic compounds with special focus on the ideal case of the CeRu2Si2 series. Discussion is made in the frame of the interplay between valence, electronic structure (Fermi surface), and magnetism. The nice tools given by the temperature, the pressure, and the magnetic field allow to explore different ground states as well as the slow downhill ''race'' before reaching a Fermi liquid finish line at very low temperature. Experimentally, the Gr"uneisen parameter i.e. the ratio of the thermal expansion by the specific heat is a coloured magic number; its temperature, pressure, and magnetic field dependence is a deep disclosure of competing hierarchies and the conversion of this adaptive matter to external responses.Comment: submitted ICM200