4,132 research outputs found

    Human brain distinctiveness based on EEG spectral coherence connectivity

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    The use of EEG biometrics, for the purpose of automatic people recognition, has received increasing attention in the recent years. Most of current analysis rely on the extraction of features characterizing the activity of single brain regions, like power-spectrum estimates, thus neglecting possible temporal dependencies between the generated EEG signals. However, important physiological information can be extracted from the way different brain regions are functionally coupled. In this study, we propose a novel approach that fuses spectral coherencebased connectivity between different brain regions as a possibly viable biometric feature. The proposed approach is tested on a large dataset of subjects (N=108) during eyes-closed (EC) and eyes-open (EO) resting state conditions. The obtained recognition performances show that using brain connectivity leads to higher distinctiveness with respect to power-spectrum measurements, in both the experimental conditions. Notably, a 100% recognition accuracy is obtained in EC and EO when integrating functional connectivity between regions in the frontal lobe, while a lower 97.41% is obtained in EC (96.26% in EO) when fusing power spectrum information from centro-parietal regions. Taken together, these results suggest that functional connectivity patterns represent effective features for improving EEG-based biometric systems.Comment: Key words: EEG, Resting state, Biometrics, Spectral coherence, Match score fusio

    Exciton-phonon scattering and photo-excitation dynamics in J-aggregate microcavities

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    We have developed a model accounting for the photo-excitation dynamics and the photoluminescence of strongly coupled J-aggregate microcavities. Our model is based on a description of the J-aggregate film as a disordered Frenkel exciton system in which relaxation occurs due to the presence of a thermal bath of molecular vibrations. In a strongly coupled microcavity exciton-polaritons are formed, mixing superradiant excitons and cavity photons. The calculation of the microcavity steady-state photoluminescence, following a CW non resonant pumping, is carried out. The experimental photoluminescence intensity ratio between upper and lower polariton branches is accurately reproduced. In particular both thermal activation of the photoluminescence intensity ratio and its Rabi splitting dependence are a consequence of the bottleneck in the relaxation, occurring at the bottom of the excitonic reservoir. The effects due to radiative channels of decay of excitons and to the presence of a paritticular set of discrete optical molecular vibrations active in relaxation processes are investigared.Comment: 8 pages, 6 figure

    Effects of atomic interactions on the resonant tunneling of sodium condensates

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    4noWe investigate the influence of atomic interactions on the tunnelling of sodium condensates across a spatially oscillating optical barrier. In the limit of very fast barrier oscillations, in which resonant tunnelling via a metastable state takes place, the interactions affect the position and lineshape of the transmission peak. We anticipate that the possibility of modulating the interactions in a tunnelling condensate can be exploited to achieve nonlinear effects such as optical limiting and bistability.openopenD. EMBRIACO; M. L. CHIOFALO; M. ARTONI; AND G. C. LA ROCCAD., Embriaco; M. L., Chiofalo; Artoni, Maurizio; AND G. C., LA ROCC

    Role of anisotropy in the F\"orster energy transfer from a semiconductor quantum well to an organic crystalline overlayer

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    We consider the non-radiative resonant energy transfer from a two-dimensional Wannier exciton (donor) to a Frenkel exciton of a molecular crystal overlayer (acceptor). We characterize the effect of the optical anisotropy of the organic subsystem on this process. Using realistic values of material parameters, we show that it is possible to change the transfer rate within typically a factor of two depending on the orientation of the crystalline overlayer. The resonant matching of donor and acceptor energies is also partly tunable via the organic crystal orientation.Comment: 6 pages, 8 figure

    Synchronization in Scale Free networks: The role of finite size effects

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    Synchronization problems in complex networks are very often studied by researchers due to its many applications to various fields such as neurobiology, e-commerce and completion of tasks. In particular, Scale Free networks with degree distribution P(k)kλP(k)\sim k^{-\lambda}, are widely used in research since they are ubiquitous in nature and other real systems. In this paper we focus on the surface relaxation growth model in Scale Free networks with 2.5<λ<32.5< \lambda <3, and study the scaling behavior of the fluctuations, in the steady state, with the system size NN. We find a novel behavior of the fluctuations characterized by a crossover between two regimes at a value of N=NN=N^* that depends on λ\lambda: a logarithmic regime, found in previous research, and a constant regime. We propose a function that describes this crossover, which is in very good agreement with the simulations. We also find that, for a system size above NN^{*}, the fluctuations decrease with λ\lambda, which means that the synchronization of the system improves as λ\lambda increases. We explain this crossover analyzing the role of the network's heterogeneity produced by the system size NN and the exponent of the degree distribution.Comment: 9 pages and 5 figures. Accepted in Europhysics Letter

    The MEV project: design and testing of a new high-resolution telescope for Muography of Etna Volcano

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    The MEV project aims at developing a muon telescope expressly designed for the muography of Etna Volcano. In particular, one of the active craters in the summit area of the volcano would be a suitable target for this experiment. A muon tracking telescope with high imaging resolution was built and tested during 2017. The telescope is a tracker based on extruded scintillating bars with WLS fibres and featuring an innovative read-out architecture. It is composed of three XY planes with a sensitive area of \SI{1}{m^2}; the angular resolution does not exceeds \SI{0.4}{\milli\steradian} and the total angular aperture is about ±\pm\SI{45}{\degree}. A special effort concerned the design of mechanics and electronics in order to meet the requirements of a detector capable to work in a hostile environment such as the top of a tall volcano, at a far distance from any facility. The test phase started in January 2017 and ended successfully at the end of July 2017. An extinct volcanic crater (the Monti Rossi, in the village of Nicolosi, about 15km from Catania) is the target of the measurement. The detector acquired data for about 120 days and the preliminary results are reported in this work

    La gestione degli autori di reati sessuali tra psicopatologia e rischio di recidiva, prospettive trattamentali

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    Sex crimes provoke alarm and strong reactions from the public to a greater extent than any other type of crimes; this occurs especially when the victims are perceived to be particularly weak subjects and/or the perpetrators are affected by psychiatric disease. For these reasons, over the last few years a growing attention has been paid to abusive sex behaviors in the medical and legal fields, leading to the introduction and development of legal procedures and alternative treatments to allow comprehensive management of the different aspects of the phenomenon. This paper analyzes the relationship between mental disorders and sex crimes. Moreover, we focus on the treatment programs offered to sex offenders in some European and North American countries and, in view of the reported results, evaluate their possible introduction in Italy. Such programs are currently in force in many countries, including the United States, Scandinavia, France, Germany, Poland and the United Kingdom. They include a first phase of evaluation of the level of risk posed by the perpetrator, followed by a treatment phase, that often includes psychiatric therapy and the use of drugs. To illustrate this type of approach, we describe the U.S. and the German experiences of subject evaluation and classification, as well as the treatments administered and the benefits observed. The data available on sex offenders show a strong risk of reiteration of the crime and therefore the need for a specific management of the problem. This has convinced certain countries to adopt specific treatment strategies, even mandatory ones, that raise ethical and legal issues, especially when they involve the mandatory use of drugs. We believe these issues warrant further in-depth analysis, as well as evaluation of the role that such programs could have in Italy

    Exposure to Endocrine Disruptors and Nuclear Receptors Gene Expression in Infertile and Fertile Men from Italian Areas with Different Environmental Features

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    Internal levels of selected endocrine disruptors (EDs) (i.e., perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), di-2-ethylhexyl-phthalate (DEHP), mono-(2-ethylhexyl)-phthalate (MEHP), and bisphenol A (BPA)) were analyzed in blood/serum of infertile and fertile men from metropolitan, urban and rural Italian areas. PFOS and PFOA levels were also evaluated in seminal plasma. In peripheral blood mononuclear cells (PBMCs) of same subjects, gene expression levels of a panel of nuclear receptors (NRs), namely estrogen receptor α (ERα) estrogen receptor β (ERβ), androgen receptor (AR), aryl hydrocarbon receptor (AhR), peroxisome proliferator-activated receptor γ (PPARγ) and pregnane X receptor (PXR) were also assessed. Infertile men from the metropolitan area had significantly higher levels of BPA and gene expression of all NRs, except PPARγ, compared to subjects from other areas. Subjects from urban areas had significantly higher levels of MEHP, whereas subjects from rural area had higher levels of PFOA in both blood and seminal plasma. Interestingly, ERα, ERβ, AR, PXR and AhR expression is directly correlated with BPA and inversely correlated with PFOA serum levels. Our study indicates the relevance of the living environment when investigating the exposure to specific EDs. Moreover, the NRs panel in PBMCs demonstrated to be a potential biomarker of effect to assess the EDs impact on reproductive health
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