Electronic phase separation near the superconductor-insulator transition of Nd1+xBa2−xCu3O7−δ thin films studied by an electric-field-induced doping effect

We report a detailed study of the transport properties of Nd(1+x)Ba(2-x)Cu(3)O(7-delta) thin films with doping changed by field effect. The data cover the whole superconducting to insulating transition and show remarkable Similarities with the effect of chemical doping in high critical temperature superconductors. The results suggest that the add-on of carriers is accompanied by an electronic phase separation, independent on the details of the doping mechanism

Urban groundwater warming in Turin area (NW Italy)

Low enthalpy, geothermal systems, alluvial, temperatur

Experimental Determination of Momentum-Resolved Electron-Phonon Coupling

We provide a novel experimental method to quantitatively estimate the electron-phonon coupling and its momentum dependence from resonant inelastic x-ray scattering (RIXS) spectra based on the detuning of the incident photon energy away from an absorption resonance. We apply it to the cuprate parent compound NdBa$_2$Cu$_3$O$_6$ and find that the electronic coupling to the oxygen half-breathing phonon mode is strongest at the Brillouin zone boundary, where it amounts to $\sim 0.17$ eV, in agreement with previous studies. In principle, this method is applicable to any absorption resonance suitable for RIXS measurements and will help to define the contribution of lattice vibrations to the peculiar properties of quantum materials.Comment: 6 pages, 3 figure

Apoptotic epitope-specific CD8+ T cells and interferon signaling intersect in chronic hepatitis C virus infection

CD8(+) T cells specific to caspase-cleaved antigens derived from apoptotic T cells represent a principal player in chronic immune activation (CIA). Here, we found that both apoptotic epitope (AE)-specific and hepatitis C virus (HCV)-specific CD8(+) T cells were mostly confined within the effector memory (EM) or terminally differentiated EM CD45RA(+) cell subsets expressing a dysfunctional T-helper-1-like signature program in chronic (c)HCV infection. However, AE-specific CD8(+) T cells produced tumor necrosis factor (TNF)-α and interleukin-2 at the intrahepatic level significantly more than HCV-specific CD8(+) T cells, despite both populations acquiring high levels of programmed death-1 receptor expression. Contextually, only AE-specific CD8(+) T cells correlated with both interferon-stimulated gene levels in T cells and hepatic fibrosis score. Taken together, these data suggest that AE-specific CD8(+) T cells can sustain CIA by their capacity to produce TNF-α and be resistant to inhibitory signals more than HCV-specific CD8(+) T cells in cHCV infection

Nanoscale modulation of the density of states at the conducting interface between LaAlO3 and SrTiO3 band insulators

The appearance of high-mobility electrons at the LaAlO3/SrTiO3 interface has raised strong interest in the material science community and a lively debate on the origin of the phenomenon. A possible explanation is an electronic reconstruction, realizing a transfer of electrons to SrTiO3 at the interface, thereby avoiding the build-up of excessive Coulomb energy as described by the "polarization catastrophe" associated with the alternating polar layers of the LaAlO3 film. Theoretical models predict that electrons are transferred into titanium 3d(xy) interface states and, in the presence of strong correlations, generate a charge and orbital order. Here we provide experimental evidence that at room temperature the local density of states of the LaAlO3/SrTiO3 conducting interface is modulated at the nanoscale in a short-range quasiperiodic pattern, which is consistent with the appearance of an orbital (short-range) order. This result, together with the splitting of the 3d states, confirms that an electronic reconstruction drives the functional properties of the LaAlO3/SrTiO3 oxide interface. The short-range superstructure does not fully agree with the theoretical predictions. Thus, further experimental and theoretical investigations are required to understand the electronic properties of the 2D electron system realised at the LaAlO3/SrTiO3 interface

Study on the water supply of the Montellina Spring by the Renanchio Stream (Quincinetto, Turin)

Tracer tests were utilised in an area of northwester Italy, in order to evaluate the hydrogeological relationship between the drinking water Montellina Spring and the Renanchio Stream, likely feeding the spring. The project of a derivation from the stream for an hydroelectric plant could affect the water regime of the spring. So an analytical assessment of the connection existing between the stream and the spring was required. Moreover, a geological survey of the spring area was carried out, with the aim to reconstruct the geological and hydrogeological context. The large amount of groundwater in the basin is linked to a high permeability of the shallow rock mass. The concentration of supplies to the spring is due to morphological reasons and the occurrence of major fractures that carry also a part of the losses of the stream. The purposes of the study are the evaluation of: the losses (l/s) of stream feeding the spring, the percentage of water of the stream that reaches the spring and the percentage of the spring discharge supplied by the stream. The hydrogeological surveys consisted of sodium-chloride tracer tests for the measurement of the stream discharge and of the overflow of the spring, and tracer tests of the stream with fluorescent tracer. The surveys were conducted in three measurement campaigns for different flows of the stream. Findings indicate that, despite the large variation of stream discharge and stream losses, the discharge of spring remains fairly steady and scarcely supplied by the stream. The case study, besides increasing the knowledge about this area, unusual for the hydrogeological features, provides a methodological approach to the evaluation of the relationship between rivers and groundwater