Sensitivity of a VIRGO pair to stochastic GW backgrounds

The sensitivity of a pair of VIRGO interferometers to gravitational waves backgrounds (GW) of cosmological origin is analyzed for the cases of maximal and minimal overlap of the two detectors. The improvements in the detectability prospects of scale-invariant and non-scale-invariant logarithmic energy spectra of relic GW are discussed.Comment: 25 pages in RevTex style with 6 figure

Prospects for Stochastic Background Searches Using Virgo and LSC Interferometers

We consider the question of cross-correlation measurements using Virgo and the LSC Interferometers (LIGO Livingston, LIGO Hanford, and GEO600) to search for a stochastic gravitational-wave background. We find that inclusion of Virgo into the network will substantially improve the sensitivity to correlations above 200 Hz if all detectors are operating at their design sensitivity. This is illustrated using a simulated isotropic stochastic background signal, generated with an astrophysically-motivated spectrum, injected into 24 hours of simulated noise for the LIGO and Virgo interferometers.Comment: 11 pages, uses IOP style files, submitted to CQG for GWDAW11 proceedings; revised in response to referee comment

On line power spectra identification and whitening for the noise in interferometric gravitational wave detectors

In this paper we address both to the problem of identifying the noise Power Spectral Density of interferometric detectors by parametric techniques and to the problem of the whitening procedure of the sequence of data. We will concentrate the study on a Power Spectral Density like the one of the Italian-French detector VIRGO and we show that with a reasonable finite number of parameters we succeed in modeling a spectrum like the theoretical one of VIRGO, reproducing all its features. We propose also the use of adaptive techniques to identify and to whiten on line the data of interferometric detectors. We analyze the behavior of the adaptive techniques in the field of stochastic gradient and in the Least Squares ones.Comment: 28 pages, 21 figures, uses iopart.cls accepted for pubblication on Classical and Quantum Gravit

Groundwater mixing in a heterogeneous multilayer aquifer driven by geogenic CO2 fluxes: Evidence from chemical and isotopic composition of Ferrarelle waters (Riardo Plain, southern Italy)

The successful management of carbon in the Earth's crust is critical for mitigating the increase of anthropogenic CO2 in the atmosphere. Carbon Capture and Storage (CCS) requires an understanding of the behavior of carbon in the crust and the development of robust monitoring techniques to constrain the movement, mechanisms, and pathways for any potential CO2 leakage. Here, we examine an aquifer from the Riardo Plain (Campania Region, southern Italy), which serves as a suitable natural analogue for CO2 migration to the critical zone (i.e., shallow crust and aquifers) and as a case study to evaluate the geochemical processes that occur when CO2-saturated fluids mix with freshwater in shallow aquifers. We investigate the behavior of various geochemical constituents (major and trace elements, δ18O–H2O, δ13C-DIC, and Rn content). Water from this area has a high degree of mineralization (EC 2500–3000 μS/cm), high HCO3- (~2.5 g/L), is saturated with respect to CaCO3, and is enriched in alkali ions (e.g., Na+ + K+). The high degree of mineralization occurs in groundwater that discharges from the basal aquifer of the Roccamonfina volcanic edifice (~6 km NW), with vast CO2 inputs that promote host rock leaching. Superficial volcanic aquifers are recharged by fresh meteoric precipitation when groundwater flows from carbonates at the edge of the plain to aquifers hosted in the southeastern slope of the Roccamonfina volcano. The presence of normal faults in this area permits natural upwelling of CO2-rich groundwater, which locally mixes with shallow freshwater present within the upper volcanic succession. Significant (R > 0.8) linear correlations between conservative elements suggest that groundwater geochemistry is dominated by a mixture of two main endmembers: (i) deep/mineralized waters and (ii) shallow/diluted waters. The intrusion of freshwater to volcanic aquifers induces oxidation, leading to adsorption of select elements (e.g., As and Ba) onto Fe-oxyhydroxide precipitates within these aquifers. Geochemical modeling suggests that CO2 saturation approaches 3 g/L, which agrees with direct measurements of CO2 flux. We conclude that our conceptual geochemical model helps to constrain mixing of CO2 with freshwater and to diagnose the secondary geochemical processes that influence aqueous geochemistry within CO2-influenced groundwater

Barrett’s esophagus: results from an Italian cohort with tight endoscopic surveillance

Background and aim: Barrett’s Esophagus represent a condition that predisposes to the development of esophageal adenocarcinoma. The aim of the present study was to analyze the demographic and clinical characteristics of patients with BE, to establish the presence of risk factors for this condition, and to determine the frequency of dysplastic lesions as well as the evolution towards adenocarcinoma under tight endoscopic control. Methods: In this study, we retrospectively collected and analyzed data from a cohort of patients with Barrett’s Esophagus identified through endoscopic records of ULSS7 in Northern Italy, who underwent upper esophago-gastroduodenoscopy over a 10-year period from July 2008 to December 2020. Results: A total of 264 patients were identified as having BE and included in the study. Mean follow-up was 6.7 years (range: 3 months-13 years). Demographic characteristics of the study population included mean age of 62.7 years (range 33-90 years), with 62.5% of the study population being aged 60 or older, and a male predominance. Females were significantly older than males (65.7 years, range 37-90 vs 61.9 years, range 33-87, p=0.043, respectively). Conclusions: The present study confirms the importance of tight endoscopic control in the management of BE, favoring early detection of BE degeneration towards high grade dysplasia or adenocarcinoma. In a subset of patients with high-risk factors including male sex, cigarette smoking and heavy alcohol intake, it may be worthwhile to consider endoscopic control over time in order to detect the development of BE. (www.actabiomedica.it)

Neutrino statistics and big bang nucleosynthesis

Neutrinos may possibly violate the spin-statistics theorem, and hence obey Bose statistics or mixed statistics despite having spin half. We find the generalized equilibrium distribution function of neutrinos which depends on a single fermi-bose parameter, \kappa, and interpolates continuously between the bosonic and fermionic distributions when \kappa changes from -1 to +1. We consider modification of the Big Bang Nucleosynthesis (BBN) in the presence of bosonic or partly bosonic neutrinos. For pure bosonic neutrinos the abundances change (in comparison with the usual Fermi-Dirac case) by -3.2% for 4He (which is equivalent to a decrease of the effective number of neutrinos by \Delta N_\nu = - 0.6), +2.6% for 2H and -7% for 7Li. These changes provide a better fit to the BBN data. Future BBN studies will be able to constrain the fermi-bose parameter to \kappa > 0.5, if no deviation from fermionic nature of neutrinos is found. We also evaluate the sensitivity of future CMB and LSS observations to the fermi-bose parameter.Comment: 11 pages, 3 figures, matches version in JCAP, discussion and references extended slightl

Microscopic derivation of Ginzburg-Landau equations for coexistent states of superconductivity and magnetism

Ginzburg-Landau (GL) equations for the coexistent states of superconductivity and magnetism are derived microscopically from the extended Hubbard model with on-site repulsive and nearest-neighbor attractive interactions. In the derived GL free energy a cubic term that couples the spin-singlet and spin-triplet components of superconducting order parameters (SCOP) with magnetization exists. This term gives rise to a spin-triplet SCOP near the interface between a spin-singlet superconductor and a ferromagnet, consistent with previous theoretical studies based on the Bogoliubov de Gennes method and the quasiclassical Green's function theory. In coexistent states of singlet superconductivity and antiferromagnetism it leads to the occurrence of pi-triplet SCOPs.Comment: 18 page